v5.1.3

changelog.md

@@ -1,5 +1,51 @@
 # Changelog
 
+## 2026-02-11 - 5.1.3 - fix(docs)
+clarify sendEmail default behavior and document automatic MX discovery and delivery modes
+
+- Updated README to describe automatic MX record discovery and grouping behavior when using sendEmail() (MTA mode)
+- Added a Delivery Modes section and API signature for sendEmail(mode) describing mta, forward, and process options
+- Expanded examples to show multi-recipient delivery, explicit mode usage, and retained low-level sendOutboundEmail example
+
+## 2026-02-11 - 5.1.2 - fix(readme)
+adjust ASCII architecture diagram alignment in README
+
+- Whitespace and alignment tweaks to the ASCII architecture diagram in readme.md
+- No code or behavior changes; documentation-only edit
+
+## 2026-02-11 - 5.1.1 - fix(release)
+no changes
+
+- No files changed in this commit.
+- Current package version remains 5.1.0 (from package.json).
+
+## 2026-02-11 - 5.1.0 - feat(mailer-smtp)
+add SCRAM-SHA-256 auth, Ed25519 DKIM, opportunistic TLS, SNI cert selection, pipelining and delivery/bridge improvements
+
+- Add server-side SCRAM-SHA-256 implementation in Rust (scram.rs) and wire up SCRAM credential request/response between Rust and TypeScript bridge (ScramCredentialRequest / scramCredentialResult).
+- Support SCRAM-SHA-256 auth mechanism in SMTP command parsing and advertise AUTH PLAIN LOGIN SCRAM-SHA-256 capability.
+- Add opportunistic TLS mode for MTA-to-MTA delivery: configurable tls_opportunistic flag, an OpportunisticVerifier that skips cert verification per RFC 7435, and plumbing into connect/upgrade TLS paths.
+- Add pipelined envelope support for MAIL FROM + multiple RCPT TO (send_pipelined_envelope) and use pipelining when server advertises PIPELINING to improve outbound performance.
+- Add Ed25519 DKIM signing support and auto-dispatch: sign_dkim_ed25519, sign_dkim_auto, dkim_dns_record_value_typed, and TS changes to detect key type and call the auto signing API.
+- Expose additional per-domain TLS certs (additionalTlsCerts) and implement SNI-based certificate resolver on the server to select certs by hostname; parsing helpers and fallback default cert handling included.
+- Install ring crypto provider early in mailer-bin main for rustls operations and add related rust dependencies (sha2, hmac, pbkdf2) and workspace entries.
+- TypeScript delivery and server bridge changes: group recipients by domain, MX resolution fallback to A record, MTA delivery loop over MX hosts, DKIM options propagation, TLS opportunistic option passed to outbound client, SCRAM credential computation in TS using PBKDF2/HMAC/SHA256 and sending results back to Rust.
+- Add new tests and utilities: IPv6 DNSBL support and tests, SCRAM unit tests, DKIM Ed25519 tests, node-level MTA delivery integration test, and various test updates.
+- Public API additions on the Rust <-> TS bridge: signDkim accepts keyType, new scram credential result command, onScramCredentialRequest/onScramCredentialResult helpers and sendScramCredentialResult.
+- Various refactors and safety/feature improvements across mailer-core/smtp/security: envelope handling, stream buffering detection, and error handling for auth flows.
+
+## 2026-02-11 - 5.0.0 - BREAKING CHANGE(mail)
+remove DMARC and DKIM verifier implementations and MTA error classes; introduce DkimManager and EmailActionExecutor; simplify SPF verifier and update routing exports and tests
+
+- Removed ts/mail/security/classes.dmarcverifier.ts and ts/mail/security/classes.dkimverifier.ts — DMARC and DKIM verifier implementations deleted
+- Removed ts/errors/index.ts — MTA-specific error classes removed
+- Added ts/mail/routing/classes.dkim.manager.ts — new DKIM key management and rotation logic
+- Added ts/mail/routing/classes.email.action.executor.ts — centralized email action execution (forward/process/deliver/reject)
+- Updated ts/mail/security/classes.spfverifier.ts to retain SPF parsing but removed verify/verifyAndApply logic delegating to Rust bridge
+- Updated ts/mail/routing/index.ts to export new routing classes and adjusted import paths (e.g. delivery queue import updated)
+- Tests trimmed: DMARC tests and rate limiter tests removed; SPF parsing test retained and simplified
+- This set of changes alters public exports and removes previously available verifier APIs — major version bump recommended
+
 ## 2026-02-11 - 4.1.1 - fix(readme)
 clarify architecture and IPC, document outbound flow and testing, and update module and crate descriptions in README
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@push.rocks/smartmta",
-  "version": "4.1.1",
+  "version": "5.1.3",
   "description": "A high-performance, enterprise-grade Mail Transfer Agent (MTA) built from scratch in TypeScript with Rust acceleration.",
   "keywords": [
     "mta",

readme.md

@@ -1,6 +1,6 @@
 # @push.rocks/smartmta
 
-A high-performance, enterprise-grade Mail Transfer Agent (MTA) built from scratch in TypeScript with a Rust-powered SMTP engine — no nodemailer, no shortcuts. 🚀
+A high-performance, enterprise-grade Mail Transfer Agent (MTA) built from scratch in TypeScript with a Rust-powered SMTP engine — no nodemailer, no shortcuts. Automatic MX record discovery means you just call `sendEmail()` and smartmta figures out where to deliver. 🚀
 
 ## Issue Reporting and Security
 
@@ -78,9 +78,10 @@ After installation, run `pnpm build` to compile the Rust binary (`mailer-bin`).
 
 **Data flow for outbound mail:**
 
-1. 📝 TypeScript constructs the email and resolves DKIM keys for the sender domain
-2. 🦀 Sends to Rust via IPC — Rust builds the RFC 2822 message, signs with DKIM, and delivers via its SMTP client with connection pooling
-3. 📬 Result (accepted/rejected recipients, server response) returned to TypeScript
+1. 📝 TypeScript constructs the email and calls `sendEmail()` (defaults to MTA mode)
+2. 🔍 MTA mode automatically resolves MX records for each recipient domain, sorts by priority, and groups recipients for efficient delivery
+3. 🦀 Sends to Rust via IPC — Rust builds the RFC 2822 message, signs with DKIM, and delivers via its SMTP client with connection pooling
+4. 📬 Result (accepted/rejected recipients, server response) returned to TypeScript
 
 ## Usage
 
@@ -169,9 +170,9 @@ await emailServer.start();
 
 > 🔒 **Note:** `start()` will throw if the Rust binary is not compiled. Run `pnpm build` first.
 
-### 📧 Sending Outbound Emails
+### 📧 Sending Emails (Automatic MX Discovery)
 
-All outbound email delivery goes through the Rust SMTP client, accessed via `UnifiedEmailServer.sendOutboundEmail()`. The Rust client handles connection pooling, TLS negotiation, and DKIM signing automatically:
+The recommended way to send email is `sendEmail()`. It defaults to **MTA mode**, which automatically resolves MX records for each recipient domain via DNS — you don't need to know the destination mail server:
 
 ```typescript
 import { Email, UnifiedEmailServer } from '@push.rocks/smartmta';
@@ -179,8 +180,7 @@ import { Email, UnifiedEmailServer } from '@push.rocks/smartmta';
 // Build an email
 const email = new Email({
   from: 'sender@example.com',
-  to: ['recipient@example.com'],
-  cc: ['cc@example.com'],
+  to: ['alice@gmail.com', 'bob@company.org'],
   subject: 'Hello from smartmta! 🚀',
   text: 'Plain text body',
   html: '<h1>Hello!</h1><p>HTML body with <strong>formatting</strong></p>',
@@ -194,7 +194,50 @@ const email = new Email({
   ],
 });
 
-// Send via the Rust SMTP client (connection pooling, TLS, DKIM signing)
+// Send — MTA mode auto-discovers MX servers for gmail.com and company.org
+const emailId = await emailServer.sendEmail(email);
+
+// Optionally specify a delivery mode explicitly
+const emailId2 = await emailServer.sendEmail(email, 'mta');
+```
+
+In MTA mode, smartmta:
+- 🔍 Resolves MX records for each recipient domain (e.g. `gmail.com`, `company.org`)
+- 📊 Sorts MX hosts by priority (lowest = highest priority per RFC 5321)
+- 🔄 Tries each MX host in order until delivery succeeds
+- 🌐 Falls back to the domain's A record if no MX records exist
+- 📦 Groups recipients by domain for efficient batch delivery
+- 🔑 Signs outbound mail with DKIM automatically
+
+### 📮 Delivery Modes
+
+`sendEmail()` accepts a mode parameter that controls how the email is delivered:
+
+```typescript
+public async sendEmail(
+  email: Email,
+  mode: EmailProcessingMode = 'mta',  // 'mta' | 'forward' | 'process'
+  route?: IEmailRoute,
+  options?: {
+    skipSuppressionCheck?: boolean;
+    ipAddress?: string;
+    isTransactional?: boolean;
+  }
+): Promise<string>
+```
+
+| Mode | Description |
+|---|---|
+| `mta` (default) | **Auto MX discovery** — resolves MX records via DNS, delivers directly to the recipient's mail server. No relay configuration needed. |
+| `forward` | **Relay delivery** — forwards the email to a configured SMTP host (e.g. an internal mail gateway or third-party relay). |
+| `process` | **Scan + deliver** — runs the content scanning / security pipeline first, then delivers via auto MX resolution. |
+
+### 📬 Direct SMTP Delivery (Low-Level)
+
+For cases where you know the exact target SMTP server (e.g. relaying to a specific host), use the lower-level `sendOutboundEmail()`:
+
+```typescript
+// Send directly to a known SMTP server (bypasses MX resolution)
 const result = await emailServer.sendOutboundEmail('smtp.example.com', 587, email, {
   auth: { user: 'sender@example.com', pass: 'your-password' },
   dkimDomain: 'example.com',

rust/Cargo.lock

@@ -982,6 +982,7 @@ dependencies = [
  "mailer-core",
  "mailer-security",
  "mailer-smtp",
+ "rustls",
  "serde",
  "serde_json",
  "tokio",
@@ -1025,15 +1026,18 @@ dependencies = [
  "base64",
  "dashmap",
  "hickory-resolver 0.25.2",
+ "hmac",
  "mailer-core",
  "mailer-security",
  "mailparse",
+ "pbkdf2",
  "regex",
  "rustls",
  "rustls-pemfile",
  "rustls-pki-types",
  "serde",
  "serde_json",
+ "sha2",
  "thiserror",
  "tokio",
  "tokio-rustls",

rust/Cargo.toml

@@ -29,3 +29,6 @@ uuid = { version = "1", features = ["v4"] }
 rustls-pki-types = "1"
 psl = "2"
 clap = { version = "4", features = ["derive"] }
+sha2 = "0.10"
+hmac = "0.12"
+pbkdf2 = { version = "0.12", default-features = false }

rust/crates/mailer-bin/Cargo.toml

@@ -21,3 +21,4 @@ hickory-resolver.workspace = true
 dashmap.workspace = true
 base64.workspace = true
 uuid.workspace = true
+rustls = { version = "0.23", default-features = false, features = ["ring", "std"] }

rust/crates/mailer-bin/src/main.rs

@@ -14,7 +14,7 @@ use std::sync::Arc;
 use tokio::sync::oneshot;
 
 use mailer_smtp::connection::{
-    AuthResult, CallbackRegistry, ConnectionEvent, EmailProcessingResult,
+    AuthResult, CallbackRegistry, ConnectionEvent, EmailProcessingResult, ScramCredentialResult,
 };
 
 /// mailer-bin: Rust-powered email security tools
@@ -114,10 +114,11 @@ struct IpcEvent {
 
 // --- Pending callbacks for correlation-ID based reverse calls ---
 
-/// Stores oneshot senders for pending email processing and auth callbacks.
+/// Stores oneshot senders for pending email processing, auth, and SCRAM callbacks.
 struct PendingCallbacks {
     email: DashMap<String, oneshot::Sender<EmailProcessingResult>>,
     auth: DashMap<String, oneshot::Sender<AuthResult>>,
+    scram: DashMap<String, oneshot::Sender<ScramCredentialResult>>,
 }
 
 impl PendingCallbacks {
@@ -125,6 +126,7 @@ impl PendingCallbacks {
         Self {
             email: DashMap::new(),
             auth: DashMap::new(),
+            scram: DashMap::new(),
         }
     }
 }
@@ -147,9 +149,22 @@ impl CallbackRegistry for PendingCallbacks {
         self.auth.insert(correlation_id.to_string(), tx);
         rx
     }
+
+    fn register_scram_callback(
+        &self,
+        correlation_id: &str,
+    ) -> oneshot::Receiver<ScramCredentialResult> {
+        let (tx, rx) = oneshot::channel();
+        self.scram.insert(correlation_id.to_string(), tx);
+        rx
+    }
 }
 
 fn main() {
+    // Install the ring CryptoProvider for rustls TLS operations (STARTTLS, implicit TLS).
+    // This must happen before any TLS connection is attempted.
+    let _ = rustls::crypto::ring::default_provider().install_default();
+
     let cli = Cli::parse();
 
     if cli.management {
@@ -494,6 +509,22 @@ fn handle_smtp_event(event: ConnectionEvent) {
                 }),
             );
         }
+        ConnectionEvent::ScramCredentialRequest {
+            correlation_id,
+            session_id,
+            username,
+            remote_addr,
+        } => {
+            emit_event(
+                "scramCredentialRequest",
+                serde_json::json!({
+                    "correlationId": correlation_id,
+                    "sessionId": session_id,
+                    "username": username,
+                    "remoteAddr": remote_addr,
+                }),
+            );
+        }
     }
 }
 
@@ -642,8 +673,13 @@ async fn handle_ipc_request(req: &IpcRequest, state: &mut ManagementState) -> Ip
                 .get("privateKey")
                 .and_then(|v| v.as_str())
                 .unwrap_or("");
+            let key_type = req
+                .params
+                .get("keyType")
+                .and_then(|v| v.as_str())
+                .unwrap_or("rsa");
 
-            match mailer_security::sign_dkim(raw_message.as_bytes(), domain, selector, private_key) {
+            match mailer_security::sign_dkim_auto(raw_message.as_bytes(), domain, selector, private_key, key_type) {
                 Ok(header) => IpcResponse {
                     id: req.id.clone(),
                     success: true,
@@ -825,6 +861,10 @@ async fn handle_ipc_request(req: &IpcRequest, state: &mut ManagementState) -> Ip
             handle_auth_result(req, state)
         }
 
+        "scramCredentialResult" => {
+            handle_scram_credential_result(req, state)
+        }
+
         "configureRateLimits" => {
             // Rate limit configuration is set at startSmtpServer time.
             // This command allows runtime updates, but for now we acknowledge it.
@@ -1010,6 +1050,56 @@ fn handle_auth_result(req: &IpcRequest, state: &ManagementState) -> IpcResponse
     }
 }
 
+/// Handle scramCredentialResult IPC command — resolves a pending SCRAM credential callback.
+fn handle_scram_credential_result(req: &IpcRequest, state: &ManagementState) -> IpcResponse {
+    use base64::Engine;
+    use base64::engine::general_purpose::STANDARD as BASE64;
+
+    let correlation_id = req
+        .params
+        .get("correlationId")
+        .and_then(|v| v.as_str())
+        .unwrap_or("");
+
+    let found = req.params.get("found").and_then(|v| v.as_bool()).unwrap_or(false);
+
+    let result = ScramCredentialResult {
+        found,
+        salt: req.params.get("salt")
+            .and_then(|v| v.as_str())
+            .and_then(|s| BASE64.decode(s.as_bytes()).ok()),
+        iterations: req.params.get("iterations")
+            .and_then(|v| v.as_u64())
+            .map(|n| n as u32),
+        stored_key: req.params.get("storedKey")
+            .and_then(|v| v.as_str())
+            .and_then(|s| BASE64.decode(s.as_bytes()).ok()),
+        server_key: req.params.get("serverKey")
+            .and_then(|v| v.as_str())
+            .and_then(|s| BASE64.decode(s.as_bytes()).ok()),
+    };
+
+    if let Some((_, tx)) = state.callbacks.scram.remove(correlation_id) {
+        let _ = tx.send(result);
+        IpcResponse {
+            id: req.id.clone(),
+            success: true,
+            result: Some(serde_json::json!({"resolved": true})),
+            error: None,
+        }
+    } else {
+        IpcResponse {
+            id: req.id.clone(),
+            success: false,
+            result: None,
+            error: Some(format!(
+                "No pending SCRAM credential callback for correlationId: {}",
+                correlation_id
+            )),
+        }
+    }
+}
+
 /// Parse SmtpServerConfig from IPC params JSON.
 fn parse_smtp_config(
     params: &serde_json::Value,
@@ -1075,6 +1165,27 @@ fn parse_smtp_config(
         config.processing_timeout_secs = timeout;
     }
 
+    // Parse additional TLS certs for SNI
+    if let Some(certs_arr) = params.get("additionalTlsCerts").and_then(|v| v.as_array()) {
+        for cert_val in certs_arr {
+            if let (Some(domains_arr), Some(cert_pem), Some(key_pem)) = (
+                cert_val.get("domains").and_then(|v| v.as_array()),
+                cert_val.get("certPem").and_then(|v| v.as_str()),
+                cert_val.get("keyPem").and_then(|v| v.as_str()),
+            ) {
+                let domains: Vec<String> = domains_arr
+                    .iter()
+                    .filter_map(|v| v.as_str().map(String::from))
+                    .collect();
+                config.additional_tls_certs.push(mailer_smtp::config::TlsDomainCert {
+                    domains,
+                    cert_pem: cert_pem.to_string(),
+                    key_pem: key_pem.to_string(),
+                });
+            }
+        }
+    }
+
     Ok(config)
 }
 
@@ -1187,11 +1298,12 @@ async fn handle_send_email(req: &IpcRequest, state: &ManagementState) -> IpcResp
     // Optional DKIM signing
     if let Some(dkim_val) = req.params.get("dkim") {
         if let Ok(dkim_config) = serde_json::from_value::<mailer_smtp::client::DkimSignConfig>(dkim_val.clone()) {
-            match mailer_security::sign_dkim(
+            match mailer_security::sign_dkim_auto(
                 &raw_message,
                 &dkim_config.domain,
                 &dkim_config.selector,
                 &dkim_config.private_key,
+                &dkim_config.key_type,
             ) {
                 Ok(header) => {
                     // Prepend DKIM header to the message

rust/crates/mailer-security/src/dkim.rs

@@ -1,4 +1,4 @@
-use mail_auth::common::crypto::{RsaKey, Sha256};
+use mail_auth::common::crypto::{Ed25519Key, RsaKey, Sha256};
 use mail_auth::common::headers::HeaderWriter;
 use mail_auth::dkim::{Canonicalization, DkimSigner};
 use mail_auth::{AuthenticatedMessage, DkimOutput, DkimResult, MessageAuthenticator};
@@ -118,9 +118,62 @@ pub fn sign_dkim(
     Ok(signature.to_header())
 }
 
+/// Sign a raw email message with DKIM using Ed25519-SHA256 (RFC 8463).
+///
+/// * `raw_message` - The raw RFC 5322 message bytes
+/// * `domain` - The signing domain (d= tag)
+/// * `selector` - The DKIM selector (s= tag)
+/// * `private_key_pkcs8_der` - Ed25519 private key in PKCS#8 DER format
+///
+/// Returns the DKIM-Signature header string to prepend to the message.
+pub fn sign_dkim_ed25519(
+    raw_message: &[u8],
+    domain: &str,
+    selector: &str,
+    private_key_pkcs8_der: &[u8],
+) -> Result<String> {
+    let ed_key = Ed25519Key::from_pkcs8_maybe_unchecked_der(private_key_pkcs8_der)
+        .map_err(|e| SecurityError::Key(format!("Failed to load Ed25519 key: {}", e)))?;
+
+    let signature = DkimSigner::from_key(ed_key)
+        .domain(domain)
+        .selector(selector)
+        .headers(["From", "To", "Subject", "Date", "Message-ID", "MIME-Version", "Content-Type"])
+        .header_canonicalization(Canonicalization::Relaxed)
+        .body_canonicalization(Canonicalization::Relaxed)
+        .sign(raw_message)
+        .map_err(|e| SecurityError::Dkim(format!("Ed25519 DKIM signing failed: {}", e)))?;
+
+    Ok(signature.to_header())
+}
+
+/// Sign a raw email message with DKIM, auto-selecting RSA or Ed25519 based on `key_type`.
+///
+/// * `key_type` - `"rsa"` (default) or `"ed25519"`
+/// * For RSA: `private_key_pem` is a PEM-encoded RSA key
+/// * For Ed25519: `private_key_pem` is a PEM-encoded PKCS#8 Ed25519 key
+pub fn sign_dkim_auto(
+    raw_message: &[u8],
+    domain: &str,
+    selector: &str,
+    private_key_pem: &str,
+    key_type: &str,
+) -> Result<String> {
+    match key_type.to_lowercase().as_str() {
+        "ed25519" => {
+            // Parse PEM to DER for Ed25519
+            let der = rustls_pki_types::PrivatePkcs8KeyDer::from_pem_slice(private_key_pem.as_bytes())
+                .map_err(|e| SecurityError::Key(format!("Failed to parse Ed25519 PEM: {}", e)))?;
+            sign_dkim_ed25519(raw_message, domain, selector, der.secret_pkcs8_der())
+        }
+        _ => sign_dkim(raw_message, domain, selector, private_key_pem),
+    }
+}
+
 /// Generate a DKIM DNS TXT record value for a given public key.
 ///
 /// Returns the value for a TXT record at `{selector}._domainkey.{domain}`.
+/// `key_type` should be `"rsa"` or `"ed25519"`.
 pub fn dkim_dns_record_value(public_key_pem: &str) -> String {
     // Extract the base64 content from PEM
     let key_b64: String = public_key_pem
@@ -132,6 +185,24 @@ pub fn dkim_dns_record_value(public_key_pem: &str) -> String {
     format!("v=DKIM1; h=sha256; k=rsa; p={}", key_b64)
 }
 
+/// Generate a DKIM DNS TXT record value with explicit key type.
+///
+/// * `key_type` - `"rsa"` or `"ed25519"`
+pub fn dkim_dns_record_value_typed(public_key_pem: &str, key_type: &str) -> String {
+    let key_b64: String = public_key_pem
+        .lines()
+        .filter(|line| !line.starts_with("-----"))
+        .collect::<Vec<_>>()
+        .join("");
+
+    let k = match key_type.to_lowercase().as_str() {
+        "ed25519" => "ed25519",
+        _ => "rsa",
+    };
+
+    format!("v=DKIM1; h=sha256; k={}; p={}", k, key_b64)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -149,4 +220,42 @@ mod tests {
         let result = sign_dkim(b"From: test@example.com\r\n\r\nBody", "example.com", "mta", "not a key");
         assert!(result.is_err());
     }
+
+    #[test]
+    fn test_sign_dkim_ed25519() {
+        // Generate an Ed25519 key pair using mail-auth
+        let pkcs8_der = Ed25519Key::generate_pkcs8().expect("generate ed25519 key");
+        let ed_key = Ed25519Key::from_pkcs8_der(&pkcs8_der).expect("parse ed25519 key");
+        let _pub_key = ed_key.public_key();
+
+        let msg = b"From: test@example.com\r\nTo: rcpt@example.com\r\nSubject: Test\r\n\r\nBody";
+        let result = sign_dkim_ed25519(msg, "example.com", "ed25519sel", &pkcs8_der);
+        assert!(result.is_ok());
+        let header = result.unwrap();
+        assert!(header.contains("a=ed25519-sha256"));
+        assert!(header.contains("d=example.com"));
+        assert!(header.contains("s=ed25519sel"));
+    }
+
+    #[test]
+    fn test_sign_dkim_auto_dispatches() {
+        // RSA with invalid key should error
+        let msg = b"From: test@example.com\r\n\r\nBody";
+        let result = sign_dkim_auto(msg, "example.com", "mta", "not a key", "rsa");
+        assert!(result.is_err());
+
+        // Ed25519 with invalid PEM should error
+        let result = sign_dkim_auto(msg, "example.com", "mta", "not a key", "ed25519");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_dkim_dns_record_value_typed() {
+        let pem = "-----BEGIN PUBLIC KEY-----\nMIIBIjANBg==\n-----END PUBLIC KEY-----";
+        let rsa_record = dkim_dns_record_value_typed(pem, "rsa");
+        assert!(rsa_record.contains("k=rsa"));
+
+        let ed_record = dkim_dns_record_value_typed(pem, "ed25519");
+        assert!(ed_record.contains("k=ed25519"));
+    }
 }

rust/crates/mailer-security/src/ip_reputation.rs

@@ -1,6 +1,6 @@
 use hickory_resolver::TokioResolver;
 use serde::{Deserialize, Serialize};
-use std::net::{IpAddr, Ipv4Addr};
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
 
 use crate::error::Result;
 
@@ -83,7 +83,7 @@ pub fn risk_level(score: u8) -> RiskLevel {
 
 /// Check an IP against DNSBL servers.
 ///
-/// * `ip` - The IP address to check (must be IPv4)
+/// * `ip` - The IP address to check (IPv4 or IPv6)
 /// * `dnsbl_servers` - DNSBL servers to query (use `DEFAULT_DNSBL_SERVERS` for defaults)
 /// * `resolver` - DNS resolver to use
 pub async fn check_dnsbl(
@@ -91,20 +91,10 @@ pub async fn check_dnsbl(
     dnsbl_servers: &[&str],
     resolver: &TokioResolver,
 ) -> Result<DnsblResult> {
-    let ipv4 = match ip {
-        IpAddr::V4(v4) => v4,
-        IpAddr::V6(_) => {
-            // IPv6 DNSBL is less common; return clean result
-            return Ok(DnsblResult {
-                ip: ip.to_string(),
-                listed_count: 0,
-                listed_on: Vec::new(),
-                total_checked: 0,
-            });
-        }
+    let reversed = match ip {
+        IpAddr::V4(v4) => reverse_ipv4(v4),
+        IpAddr::V6(v6) => reverse_ipv6(v6),
     };
-
-    let reversed = reverse_ipv4(ipv4);
     let total = dnsbl_servers.len();
 
     // Query all DNSBL servers in parallel
@@ -178,6 +168,21 @@ fn reverse_ipv4(ip: Ipv4Addr) -> String {
     format!("{}.{}.{}.{}", octets[3], octets[2], octets[1], octets[0])
 }
 
+/// Reverse IPv6 address to nibble format for DNSBL queries.
+///
+/// Expands to full 32-nibble hex, reverses, and dot-separates each nibble.
+/// E.g. `2001:db8::1` -> `1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2`
+fn reverse_ipv6(ip: Ipv6Addr) -> String {
+    let segments = ip.segments();
+    let full_hex: String = segments.iter().map(|s| format!("{:04x}", s)).collect();
+    full_hex
+        .chars()
+        .rev()
+        .map(|c| c.to_string())
+        .collect::<Vec<_>>()
+        .join(".")
+}
+
 /// Heuristic IP type classification based on well-known prefix ranges.
 /// Same heuristics as the TypeScript IPReputationChecker.
 fn classify_ip(ip: IpAddr) -> IpType {
@@ -272,6 +277,38 @@ mod tests {
         assert!(!is_valid_ipv4("not-an-ip"));
     }
 
+    #[test]
+    fn test_reverse_ipv6() {
+        let ip: Ipv6Addr = "2001:0db8:0000:0000:0000:0000:0000:0001".parse().unwrap();
+        assert_eq!(
+            reverse_ipv6(ip),
+            "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2"
+        );
+    }
+
+    #[test]
+    fn test_reverse_ipv6_loopback() {
+        let ip: Ipv6Addr = "::1".parse().unwrap();
+        assert_eq!(
+            reverse_ipv6(ip),
+            "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0"
+        );
+    }
+
+    #[tokio::test]
+    async fn test_check_dnsbl_ipv6_runs() {
+        // Verify IPv6 actually goes through DNSBL queries (not skipped)
+        let resolver = hickory_resolver::TokioResolver::builder_tokio()
+            .map(|b| b.build())
+            .unwrap();
+        let ip: IpAddr = "::1".parse().unwrap();
+        let result = check_dnsbl(ip, DEFAULT_DNSBL_SERVERS, &resolver).await.unwrap();
+        // Loopback should not be listed on any DNSBL
+        assert_eq!(result.listed_count, 0);
+        // But total_checked should be > 0 — proving IPv6 was actually queried
+        assert_eq!(result.total_checked, DEFAULT_DNSBL_SERVERS.len());
+    }
+
     #[test]
     fn test_default_dnsbl_servers() {
         assert_eq!(DEFAULT_DNSBL_SERVERS.len(), 10);

rust/crates/mailer-security/src/lib.rs

@@ -9,7 +9,7 @@ pub mod spf;
 pub mod verify;
 
 // Re-exports for convenience
-pub use dkim::{dkim_dns_record_value, dkim_outputs_to_results, sign_dkim, verify_dkim, DkimVerificationResult};
+pub use dkim::{dkim_dns_record_value, dkim_dns_record_value_typed, dkim_outputs_to_results, sign_dkim, sign_dkim_auto, sign_dkim_ed25519, verify_dkim, DkimVerificationResult};
 pub use dmarc::{check_dmarc, DmarcPolicy, DmarcResult};
 pub use verify::{verify_email_security, EmailSecurityResult};
 pub use error::{Result, SecurityError};

rust/crates/mailer-smtp/Cargo.toml

@@ -23,3 +23,6 @@ rustls = { version = "0.23", default-features = false, features = ["ring", "logg
 rustls-pemfile = "2"
 mailparse.workspace = true
 webpki-roots = "0.26"
+sha2.workspace = true
+hmac.workspace = true
+pbkdf2.workspace = true

rust/crates/mailer-smtp/src/client/config.rs

@@ -37,6 +37,12 @@ pub struct SmtpClientConfig {
     /// Maximum connections per pool. Default: 10.
     #[serde(default = "default_max_pool_connections")]
     pub max_pool_connections: usize,
+
+    /// Accept invalid TLS certificates (expired, self-signed, wrong hostname).
+    /// Standard for MTA-to-MTA opportunistic TLS per RFC 7435.
+    /// Default: false.
+    #[serde(default)]
+    pub tls_opportunistic: bool,
 }
 
 /// Authentication configuration.
@@ -60,8 +66,15 @@ pub struct DkimSignConfig {
     pub domain: String,
     /// DKIM selector (e.g. "default" or "mta").
     pub selector: String,
-    /// PEM-encoded RSA private key.
+    /// PEM-encoded private key (RSA or Ed25519 PKCS#8).
     pub private_key: String,
+    /// Key type: "rsa" (default) or "ed25519".
+    #[serde(default = "default_key_type")]
+    pub key_type: String,
+}
+
+fn default_key_type() -> String {
+    "rsa".to_string()
 }
 
 impl SmtpClientConfig {

rust/crates/mailer-smtp/src/client/connection.rs

@@ -117,6 +117,7 @@ pub async fn connect_tls(
     host: &str,
     port: u16,
     timeout_secs: u64,
+    tls_opportunistic: bool,
 ) -> Result<ClientSmtpStream, SmtpClientError> {
     debug!("Connecting to {}:{} (implicit TLS)", host, port);
     let addr = format!("{host}:{port}");
@@ -130,7 +131,7 @@ pub async fn connect_tls(
             message: format!("Failed to connect to {addr}: {e}"),
         })?;
 
-    let tls_stream = perform_tls_handshake(tcp_stream, host).await?;
+    let tls_stream = perform_tls_handshake(tcp_stream, host, tls_opportunistic).await?;
     Ok(ClientSmtpStream::Tls(BufReader::new(tls_stream)))
 }
 
@@ -138,24 +139,77 @@ pub async fn connect_tls(
 pub async fn upgrade_to_tls(
     stream: ClientSmtpStream,
     hostname: &str,
+    tls_opportunistic: bool,
 ) -> Result<ClientSmtpStream, SmtpClientError> {
     debug!("Upgrading connection to TLS (STARTTLS) for {}", hostname);
     let tcp_stream = stream.into_tcp_stream()?;
-    let tls_stream = perform_tls_handshake(tcp_stream, hostname).await?;
+    let tls_stream = perform_tls_handshake(tcp_stream, hostname, tls_opportunistic).await?;
     Ok(ClientSmtpStream::Tls(BufReader::new(tls_stream)))
 }
 
+/// A TLS certificate verifier that accepts any certificate.
+/// Used for MTA-to-MTA opportunistic TLS per RFC 7435.
+#[derive(Debug)]
+struct OpportunisticVerifier;
+
+impl rustls::client::danger::ServerCertVerifier for OpportunisticVerifier {
+    fn verify_server_cert(
+        &self,
+        _end_entity: &rustls_pki_types::CertificateDer<'_>,
+        _intermediates: &[rustls_pki_types::CertificateDer<'_>],
+        _server_name: &rustls_pki_types::ServerName<'_>,
+        _ocsp_response: &[u8],
+        _now: rustls_pki_types::UnixTime,
+    ) -> Result<rustls::client::danger::ServerCertVerified, rustls::Error> {
+        Ok(rustls::client::danger::ServerCertVerified::assertion())
+    }
+
+    fn verify_tls12_signature(
+        &self,
+        _message: &[u8],
+        _cert: &rustls_pki_types::CertificateDer<'_>,
+        _dss: &rustls::DigitallySignedStruct,
+    ) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
+        Ok(rustls::client::danger::HandshakeSignatureValid::assertion())
+    }
+
+    fn verify_tls13_signature(
+        &self,
+        _message: &[u8],
+        _cert: &rustls_pki_types::CertificateDer<'_>,
+        _dss: &rustls::DigitallySignedStruct,
+    ) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
+        Ok(rustls::client::danger::HandshakeSignatureValid::assertion())
+    }
+
+    fn supported_verify_schemes(&self) -> Vec<rustls::SignatureScheme> {
+        rustls::crypto::ring::default_provider()
+            .signature_verification_algorithms
+            .supported_schemes()
+    }
+}
+
 /// Perform the TLS handshake on a TCP stream using webpki-roots.
+/// When `tls_opportunistic` is true, certificate verification is skipped
+/// (standard for MTA-to-MTA delivery per RFC 7435).
 async fn perform_tls_handshake(
     tcp_stream: TcpStream,
     hostname: &str,
+    tls_opportunistic: bool,
 ) -> Result<TlsStream<TcpStream>, SmtpClientError> {
+    let tls_config = if tls_opportunistic {
+        debug!("Using opportunistic TLS (no cert verification) for {}", hostname);
+        rustls::ClientConfig::builder()
+            .dangerous()
+            .with_custom_certificate_verifier(Arc::new(OpportunisticVerifier))
+            .with_no_client_auth()
+    } else {
         let mut root_store = rustls::RootCertStore::empty();
         root_store.extend(webpki_roots::TLS_SERVER_ROOTS.iter().cloned());
-
-    let tls_config = rustls::ClientConfig::builder()
+        rustls::ClientConfig::builder()
             .with_root_certificates(root_store)
-        .with_no_client_auth();
+            .with_no_client_auth()
+    };
 
     let connector = tokio_rustls::TlsConnector::from(Arc::new(tls_config));
     let server_name = rustls_pki_types::ServerName::try_from(hostname.to_string()).map_err(|e| {
@@ -190,7 +244,7 @@ mod tests {
 
     #[tokio::test]
     async fn test_connect_tls_refused() {
-        let result = connect_tls("127.0.0.1", 19998, 2).await;
+        let result = connect_tls("127.0.0.1", 19998, 2, false).await;
         assert!(result.is_err());
     }
 

rust/crates/mailer-smtp/src/client/pool.rs

@@ -116,6 +116,7 @@ impl ConnectionPool {
                 &self.config.host,
                 self.config.port,
                 self.config.connection_timeout_secs,
+                self.config.tls_opportunistic,
             )
             .await?
         } else {
@@ -139,7 +140,7 @@ impl ConnectionPool {
         if !self.config.secure && capabilities.starttls {
             protocol::send_starttls(&mut stream, self.config.socket_timeout_secs).await?;
             stream =
-                super::connection::upgrade_to_tls(stream, &self.config.host).await?;
+                super::connection::upgrade_to_tls(stream, &self.config.host, self.config.tls_opportunistic).await?;
 
             // Re-EHLO after STARTTLS — use updated capabilities for auth
             capabilities = protocol::send_ehlo(
@@ -244,9 +245,10 @@ impl SmtpClientManager {
             protocol::send_rset(&mut conn.stream, config.socket_timeout_secs).await?;
         }
 
-        // Perform the SMTP transaction
+        // Perform the SMTP transaction (use pipelining if server supports it)
+        let pipelining = conn.capabilities.pipelining;
         let result =
-            Self::perform_send(&mut conn.stream, sender, recipients, message, config).await;
+            Self::perform_send(&mut conn.stream, sender, recipients, message, config, pipelining).await;
 
         // Re-acquire the pool lock and release the connection
         let mut pool = pool_arc.lock().await;
@@ -268,13 +270,20 @@ impl SmtpClientManager {
         recipients: &[String],
         message: &[u8],
         config: &SmtpClientConfig,
+        pipelining: bool,
     ) -> Result<SmtpSendResult, SmtpClientError> {
         let timeout_secs = config.socket_timeout_secs;
 
-        // MAIL FROM
+        let (accepted, rejected) = if pipelining {
+            // Use pipelined envelope: MAIL FROM + all RCPT TO in one batch
+            let (_mail_ok, acc, rej) = protocol::send_pipelined_envelope(
+                stream, sender, recipients, timeout_secs,
+            ).await?;
+            (acc, rej)
+        } else {
+            // Sequential: MAIL FROM, then each RCPT TO
             protocol::send_mail_from(stream, sender, timeout_secs).await?;
 
-        // RCPT TO for each recipient
             let mut accepted = Vec::new();
             let mut rejected = Vec::new();
 
@@ -292,6 +301,8 @@ impl SmtpClientManager {
                     }
                 }
             }
+            (accepted, rejected)
+        };
 
         // If no recipients were accepted, fail
         if accepted.is_empty() {
@@ -339,6 +350,7 @@ impl SmtpClientManager {
                 &config.host,
                 config.port,
                 config.connection_timeout_secs,
+                config.tls_opportunistic,
             )
             .await?
         } else {

rust/crates/mailer-smtp/src/client/protocol.rs

@@ -318,6 +318,54 @@ pub async fn send_rcpt_to(
     Ok(resp)
 }
 
+/// Send MAIL FROM + RCPT TO commands in a single pipelined batch.
+///
+/// Writes all envelope commands at once, then reads responses in order.
+/// Returns `(mail_from_ok, accepted_recipients, rejected_recipients)`.
+pub async fn send_pipelined_envelope(
+    stream: &mut ClientSmtpStream,
+    sender: &str,
+    recipients: &[String],
+    timeout_secs: u64,
+) -> Result<(bool, Vec<String>, Vec<String>), SmtpClientError> {
+    // Build the full pipelined command batch
+    let mut batch = format!("MAIL FROM:<{sender}>\r\n");
+    for rcpt in recipients {
+        batch.push_str(&format!("RCPT TO:<{rcpt}>\r\n"));
+    }
+
+    // Send all commands at once
+    debug!("SMTP C (pipelined): MAIL FROM + {} RCPT TO", recipients.len());
+    stream.write_all(batch.as_bytes()).await?;
+    stream.flush().await?;
+
+    // Read MAIL FROM response
+    let mail_resp = read_response(stream, timeout_secs).await?;
+    if !mail_resp.is_success() {
+        return Err(mail_resp.to_error());
+    }
+
+    // Read RCPT TO responses
+    let mut accepted = Vec::new();
+    let mut rejected = Vec::new();
+    for rcpt in recipients {
+        match read_response(stream, timeout_secs).await {
+            Ok(resp) => {
+                if resp.is_success() {
+                    accepted.push(rcpt.clone());
+                } else {
+                    rejected.push(rcpt.clone());
+                }
+            }
+            Err(_) => {
+                rejected.push(rcpt.clone());
+            }
+        }
+    }
+
+    Ok((true, accepted, rejected))
+}
+
 /// Send DATA command, followed by the message body with dot-stuffing.
 pub async fn send_data(
     stream: &mut ClientSmtpStream,

rust/crates/mailer-smtp/src/command.rs

@@ -50,6 +50,7 @@ pub enum SmtpCommand {
 pub enum AuthMechanism {
     Plain,
     Login,
+    ScramSha256,
 }
 
 /// Errors that can occur during command parsing.
@@ -218,6 +219,7 @@ fn parse_auth(rest: &str) -> Result<SmtpCommand, ParseError> {
     let mechanism = match mech_str.to_ascii_uppercase().as_str() {
         "PLAIN" => AuthMechanism::Plain,
         "LOGIN" => AuthMechanism::Login,
+        "SCRAM-SHA-256" => AuthMechanism::ScramSha256,
         other => {
             return Err(ParseError::SyntaxError(format!(
                 "unsupported AUTH mechanism: {other}"

rust/crates/mailer-smtp/src/config.rs

@@ -2,6 +2,17 @@
 
 use serde::{Deserialize, Serialize};
 
+/// Per-domain TLS certificate for SNI-based cert selection.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct TlsDomainCert {
+    /// Domain names this certificate covers (matched against SNI hostname).
+    pub domains: Vec<String>,
+    /// Certificate chain in PEM format.
+    pub cert_pem: String,
+    /// Private key in PEM format.
+    pub key_pem: String,
+}
+
 /// Configuration for an SMTP server instance.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct SmtpServerConfig {
@@ -11,10 +22,13 @@ pub struct SmtpServerConfig {
     pub ports: Vec<u16>,
     /// Port for implicit TLS (e.g. 465). None = no implicit TLS port.
     pub secure_port: Option<u16>,
-    /// TLS certificate chain in PEM format.
+    /// TLS certificate chain in PEM format (default cert).
     pub tls_cert_pem: Option<String>,
-    /// TLS private key in PEM format.
+    /// TLS private key in PEM format (default key).
     pub tls_key_pem: Option<String>,
+    /// Additional per-domain TLS certificates for SNI-based selection.
+    #[serde(default)]
+    pub additional_tls_certs: Vec<TlsDomainCert>,
     /// Maximum message size in bytes.
     pub max_message_size: u64,
     /// Maximum number of concurrent connections.
@@ -43,6 +57,7 @@ impl Default for SmtpServerConfig {
             secure_port: None,
             tls_cert_pem: None,
             tls_key_pem: None,
+            additional_tls_certs: Vec::new(),
             max_message_size: 10 * 1024 * 1024, // 10 MB
             max_connections: 100,
             max_recipients: 100,

rust/crates/mailer-smtp/src/connection.rs

@@ -9,6 +9,7 @@ use crate::config::SmtpServerConfig;
 use crate::data::{DataAccumulator, DataAction};
 use crate::rate_limiter::RateLimiter;
 use crate::response::{build_capabilities, SmtpResponse};
+use crate::scram::{ScramCredentials, ScramServer};
 use crate::session::{AuthState, SmtpSession};
 use crate::validation;
 
@@ -52,6 +53,13 @@ pub enum ConnectionEvent {
         password: String,
         remote_addr: String,
     },
+    /// A SCRAM credential request — Rust needs stored credentials from TS.
+    ScramCredentialRequest {
+        correlation_id: String,
+        session_id: String,
+        username: String,
+        remote_addr: String,
+    },
 }
 
 /// How email data is transported from Rust to TS.
@@ -81,6 +89,16 @@ pub struct AuthResult {
     pub message: Option<String>,
 }
 
+/// Result of TS returning SCRAM credentials for a user.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ScramCredentialResult {
+    pub found: bool,
+    pub salt: Option<Vec<u8>>,
+    pub iterations: Option<u32>,
+    pub stored_key: Option<Vec<u8>>,
+    pub server_key: Option<Vec<u8>>,
+}
+
 /// Abstraction over plain and TLS streams.
 pub enum SmtpStream {
     Plain(BufReader<TcpStream>),
@@ -133,6 +151,14 @@ impl SmtpStream {
         }
     }
 
+    /// Check if the internal buffer has unread data (pipelined commands).
+    pub fn has_buffered_data(&self) -> bool {
+        match self {
+            SmtpStream::Plain(reader) => !reader.buffer().is_empty(),
+            SmtpStream::Tls(reader) => !reader.buffer().is_empty(),
+        }
+    }
+
     /// Unwrap to get the raw TcpStream for STARTTLS upgrade.
     /// Only works on Plain streams.
     pub fn into_tcp_stream(self) -> Option<TcpStream> {
@@ -212,7 +238,7 @@ pub async fn handle_connection(
                 break;
             }
             Ok(Ok(_)) => {
-                // Process command
+                // Process the first command
                 let response = process_line(
                     &line,
                     &mut session,
@@ -227,21 +253,92 @@ pub async fn handle_connection(
                 )
                 .await;
 
+                // Check for pipelined commands in the buffer.
+                // Collect pipelinable responses into a batch for single write.
+                let mut response_batch: Vec<u8> = Vec::new();
+                let mut should_break = false;
+                let mut starttls_signal = false;
+
                 match response {
                     LineResult::Response(resp) => {
-                        if stream.write_all(&resp.to_bytes()).await.is_err() {
+                        response_batch.extend_from_slice(&resp.to_bytes());
+                    }
+                    LineResult::Quit(resp) => {
+                        let _ = stream.write_all(&resp.to_bytes()).await;
+                        let _ = stream.flush().await;
+                        should_break = true;
+                    }
+                    LineResult::StartTlsSignal => {
+                        starttls_signal = true;
+                    }
+                    LineResult::NoResponse => {}
+                    LineResult::Disconnect => {
+                        should_break = true;
+                    }
+                }
+
+                if should_break {
+                    break;
+                }
+
+                // Process additional pipelined commands from the buffer
+                if !starttls_signal {
+                    while stream.has_buffered_data() {
+                        let mut next_line = String::new();
+                        match stream.read_line(&mut next_line, 4096).await {
+                            Ok(0) | Err(_) => break,
+                            Ok(_) => {
+                                let next_response = process_line(
+                                    &next_line,
+                                    &mut session,
+                                    &mut stream,
+                                    &config,
+                                    &rate_limiter,
+                                    &event_tx,
+                                    callback_register.as_ref(),
+                                    &tls_acceptor,
+                                    &authenticator,
+                                    &resolver,
+                                )
+                                .await;
+
+                                match next_response {
+                                    LineResult::Response(resp) => {
+                                        response_batch.extend_from_slice(&resp.to_bytes());
+                                    }
+                                    LineResult::Quit(resp) => {
+                                        response_batch.extend_from_slice(&resp.to_bytes());
+                                        should_break = true;
+                                        break;
+                                    }
+                                    LineResult::StartTlsSignal | LineResult::Disconnect => {
+                                        // Non-pipelinable: flush batch and handle
+                                        starttls_signal = matches!(next_response, LineResult::StartTlsSignal);
+                                        should_break = matches!(next_response, LineResult::Disconnect);
+                                        break;
+                                    }
+                                    LineResult::NoResponse => {}
+                                }
+                            }
+                        }
+                    }
+                }
+
+                // Flush the accumulated response batch in one write
+                if !response_batch.is_empty() {
+                    if stream.write_all(&response_batch).await.is_err() {
                         break;
                     }
                     if stream.flush().await.is_err() {
                         break;
                     }
                 }
-                    LineResult::Quit(resp) => {
-                        let _ = stream.write_all(&resp.to_bytes()).await;
-                        let _ = stream.flush().await;
+
+                if should_break {
                     break;
                 }
-                    LineResult::StartTlsSignal => {
+
+                if starttls_signal {
                     // Send 220 Ready response
                     let resp = SmtpResponse::new(220, "Ready to start TLS");
                     if stream.write_all(&resp.to_bytes()).await.is_err() {
@@ -257,7 +354,6 @@ pub async fn handle_connection(
                                 Ok(tls_stream) => {
                                     stream = SmtpStream::Tls(BufReader::new(tls_stream));
                                     session.secure = true;
-                                        // Client must re-EHLO after STARTTLS
                                     session.state = crate::state::SmtpState::Connected;
                                     session.client_hostname = None;
                                     session.esmtp = false;
@@ -274,12 +370,6 @@ pub async fn handle_connection(
                             break;
                         }
                     } else {
-                            // Already TLS — shouldn't happen
-                            break;
-                        }
-                    }
-                    LineResult::NoResponse => {}
-                    LineResult::Disconnect => {
                         break;
                     }
                 }
@@ -322,6 +412,12 @@ pub trait CallbackRegistry: Send + Sync {
         &self,
         correlation_id: &str,
     ) -> oneshot::Receiver<AuthResult>;
+
+    /// Register a callback for SCRAM credential lookup and return a receiver.
+    fn register_scram_callback(
+        &self,
+        correlation_id: &str,
+    ) -> oneshot::Receiver<ScramCredentialResult>;
 }
 
 /// Process a single input line from the client.
@@ -406,6 +502,18 @@ async fn process_line(
             mechanism,
             initial_response,
         } => {
+            if matches!(mechanism, AuthMechanism::ScramSha256) {
+                handle_auth_scram(
+                    initial_response,
+                    session,
+                    stream,
+                    config,
+                    rate_limiter,
+                    event_tx,
+                    callback_registry,
+                )
+                .await
+            } else {
                 handle_auth(
                     mechanism,
                     initial_response,
@@ -417,6 +525,7 @@ async fn process_line(
                 )
                 .await
             }
+        }
 
         SmtpCommand::Help(_) => {
             LineResult::Response(SmtpResponse::new(
@@ -832,6 +941,217 @@ async fn handle_auth(
                 ))
             }
         }
+        AuthMechanism::ScramSha256 => {
+            // SCRAM is handled separately in process_line; this should not be reached.
+            LineResult::Response(SmtpResponse::not_implemented())
+        }
+    }
+}
+
+/// Handle AUTH SCRAM-SHA-256 — full exchange in a single async function.
+///
+/// SCRAM is a multi-step challenge-response protocol:
+/// 1. Client sends client-first-message (in initial_response or after 334)
+/// 2. Server requests SCRAM credentials from TS
+/// 3. Server sends server-first-message (334 challenge)
+/// 4. Client sends client-final-message (proof)
+/// 5. Server verifies proof and responds with 235 or 535
+async fn handle_auth_scram(
+    initial_response: Option<String>,
+    session: &mut SmtpSession,
+    stream: &mut SmtpStream,
+    config: &SmtpServerConfig,
+    rate_limiter: &RateLimiter,
+    event_tx: &mpsc::Sender<ConnectionEvent>,
+    callback_registry: &dyn CallbackRegistry,
+) -> LineResult {
+    if !config.auth_enabled {
+        return LineResult::Response(SmtpResponse::not_implemented());
+    }
+
+    if session.is_authenticated() {
+        return LineResult::Response(SmtpResponse::bad_sequence("Already authenticated"));
+    }
+
+    if !session.state.can_auth() {
+        return LineResult::Response(SmtpResponse::bad_sequence("Send EHLO first"));
+    }
+
+    // Step 1: Get client-first-message
+    let client_first_b64 = match initial_response {
+        Some(s) if !s.is_empty() => s,
+        _ => {
+            // No initial response — send empty 334 challenge
+            let resp = SmtpResponse::auth_challenge("");
+            if stream.write_all(&resp.to_bytes()).await.is_err() {
+                return LineResult::Disconnect;
+            }
+            if stream.flush().await.is_err() {
+                return LineResult::Disconnect;
+            }
+            // Read client-first-message
+            let mut line = String::new();
+            let socket_timeout = Duration::from_secs(config.socket_timeout_secs);
+            match timeout(socket_timeout, stream.read_line(&mut line, 4096)).await {
+                Err(_) | Ok(Err(_)) | Ok(Ok(0)) => return LineResult::Disconnect,
+                Ok(Ok(_)) => {}
+            }
+            let trimmed = line.trim().to_string();
+            if trimmed == "*" {
+                return LineResult::Response(SmtpResponse::new(501, "Authentication cancelled"));
+            }
+            trimmed
+        }
+    };
+
+    // Decode base64 client-first-message
+    let client_first_bytes = match BASE64.decode(client_first_b64.as_bytes()) {
+        Ok(b) => b,
+        Err(_) => {
+            return LineResult::Response(SmtpResponse::param_error("Invalid base64 encoding"));
+        }
+    };
+    let client_first = match String::from_utf8(client_first_bytes) {
+        Ok(s) => s,
+        Err(_) => {
+            return LineResult::Response(SmtpResponse::param_error("Invalid UTF-8 in SCRAM message"));
+        }
+    };
+
+    // Parse client-first-message
+    let mut scram = match ScramServer::from_client_first(&client_first) {
+        Ok(s) => s,
+        Err(e) => {
+            debug!(error = %e, "SCRAM client-first-message parse error");
+            return LineResult::Response(SmtpResponse::param_error(
+                "Invalid SCRAM client-first-message",
+            ));
+        }
+    };
+
+    // Step 2: Request SCRAM credentials from TS
+    let correlation_id = uuid::Uuid::new_v4().to_string();
+    let rx = callback_registry.register_scram_callback(&correlation_id);
+
+    let event = ConnectionEvent::ScramCredentialRequest {
+        correlation_id: correlation_id.clone(),
+        session_id: session.id.clone(),
+        username: scram.username.clone(),
+        remote_addr: session.remote_addr.clone(),
+    };
+
+    if event_tx.send(event).await.is_err() {
+        return LineResult::Response(SmtpResponse::local_error("Internal processing error"));
+    }
+
+    // Wait for credentials from TS
+    let cred_timeout = Duration::from_secs(5);
+    let cred_result = match timeout(cred_timeout, rx).await {
+        Ok(Ok(result)) => result,
+        Ok(Err(_)) => {
+            warn!(correlation_id = %correlation_id, "SCRAM credential callback dropped");
+            return LineResult::Response(SmtpResponse::local_error("Internal processing error"));
+        }
+        Err(_) => {
+            warn!(correlation_id = %correlation_id, "SCRAM credential request timed out");
+            return LineResult::Response(SmtpResponse::local_error("Internal processing error"));
+        }
+    };
+
+    if !cred_result.found {
+        // User not found — fail auth (don't reveal that user doesn't exist)
+        session.auth_state = AuthState::None;
+        let exceeded = session.record_auth_failure(config.max_auth_failures);
+        if exceeded {
+            return LineResult::Quit(SmtpResponse::service_unavailable(
+                &config.hostname,
+                "Too many authentication failures",
+            ));
+        }
+        return LineResult::Response(SmtpResponse::auth_failed());
+    }
+
+    let creds = ScramCredentials {
+        salt: cred_result.salt.unwrap_or_default(),
+        iterations: cred_result.iterations.unwrap_or(4096),
+        stored_key: cred_result.stored_key.unwrap_or_default(),
+        server_key: cred_result.server_key.unwrap_or_default(),
+    };
+
+    // Step 3: Generate and send server-first-message
+    let server_first = scram.server_first_message(creds);
+    let server_first_b64 = BASE64.encode(server_first.as_bytes());
+
+    let challenge = SmtpResponse::auth_challenge(&server_first_b64);
+    if stream.write_all(&challenge.to_bytes()).await.is_err() {
+        return LineResult::Disconnect;
+    }
+    if stream.flush().await.is_err() {
+        return LineResult::Disconnect;
+    }
+
+    // Step 4: Read client-final-message
+    let mut client_final_line = String::new();
+    let socket_timeout = Duration::from_secs(config.socket_timeout_secs);
+    match timeout(socket_timeout, stream.read_line(&mut client_final_line, 4096)).await {
+        Err(_) | Ok(Err(_)) | Ok(Ok(0)) => return LineResult::Disconnect,
+        Ok(Ok(_)) => {}
+    }
+
+    let client_final_b64 = client_final_line.trim();
+
+    // Cancel if *
+    if client_final_b64 == "*" {
+        session.auth_state = AuthState::None;
+        return LineResult::Response(SmtpResponse::new(501, "Authentication cancelled"));
+    }
+
+    // Decode base64 client-final-message
+    let client_final_bytes = match BASE64.decode(client_final_b64.as_bytes()) {
+        Ok(b) => b,
+        Err(_) => {
+            session.auth_state = AuthState::None;
+            return LineResult::Response(SmtpResponse::param_error("Invalid base64 encoding"));
+        }
+    };
+    let client_final = match String::from_utf8(client_final_bytes) {
+        Ok(s) => s,
+        Err(_) => {
+            session.auth_state = AuthState::None;
+            return LineResult::Response(SmtpResponse::param_error("Invalid UTF-8 in SCRAM message"));
+        }
+    };
+
+    // Step 5: Verify proof
+    match scram.process_client_final(&client_final) {
+        Ok(server_final) => {
+            let server_final_b64 = BASE64.encode(server_final.as_bytes());
+            session.auth_state = AuthState::Authenticated {
+                username: scram.username.clone(),
+            };
+            LineResult::Response(SmtpResponse::new(
+                235,
+                format!("2.7.0 Authentication successful {}", server_final_b64),
+            ))
+        }
+        Err(e) => {
+            debug!(error = %e, "SCRAM proof verification failed");
+            session.auth_state = AuthState::None;
+            let exceeded = session.record_auth_failure(config.max_auth_failures);
+            if exceeded {
+                if !rate_limiter.check_auth_failure(&session.remote_addr) {
+                    return LineResult::Quit(SmtpResponse::service_unavailable(
+                        &config.hostname,
+                        "Too many authentication failures",
+                    ));
+                }
+                return LineResult::Quit(SmtpResponse::service_unavailable(
+                    &config.hostname,
+                    "Too many authentication failures",
+                ));
+            }
+            LineResult::Response(SmtpResponse::auth_failed())
+        }
     }
 }
 

rust/crates/mailer-smtp/src/lib.rs

@@ -19,6 +19,7 @@ pub mod connection;
 pub mod data;
 pub mod rate_limiter;
 pub mod response;
+pub mod scram;
 pub mod server;
 pub mod session;
 pub mod state;

rust/crates/mailer-smtp/src/response.rs

@@ -196,7 +196,7 @@ pub fn build_capabilities(
         caps.push("STARTTLS".to_string());
     }
     if auth_available {
-        caps.push("AUTH PLAIN LOGIN".to_string());
+        caps.push("AUTH PLAIN LOGIN SCRAM-SHA-256".to_string());
     }
     caps
 }
@@ -253,7 +253,7 @@ mod tests {
         let caps = build_capabilities(10485760, true, false, true);
         assert!(caps.contains(&"SIZE 10485760".to_string()));
         assert!(caps.contains(&"STARTTLS".to_string()));
-        assert!(caps.contains(&"AUTH PLAIN LOGIN".to_string()));
+        assert!(caps.contains(&"AUTH PLAIN LOGIN SCRAM-SHA-256".to_string()));
         assert!(caps.contains(&"PIPELINING".to_string()));
     }
 
@@ -262,7 +262,7 @@ mod tests {
         // When already secure, STARTTLS should NOT be advertised
         let caps = build_capabilities(10485760, true, true, false);
         assert!(!caps.contains(&"STARTTLS".to_string()));
-        assert!(!caps.contains(&"AUTH PLAIN LOGIN".to_string()));
+        assert!(!caps.contains(&"AUTH PLAIN LOGIN SCRAM-SHA-256".to_string()));
     }
 
     #[test]

rust/crates/mailer-smtp/src/scram.rs

@@ -0,0 +1,342 @@
+//! SCRAM-SHA-256 server-side implementation (RFC 5802 + RFC 7677).
+//!
+//! Implements the server side of the SCRAM-SHA-256 SASL mechanism,
+//! a challenge-response protocol that avoids transmitting cleartext passwords.
+
+use base64::engine::general_purpose::STANDARD as BASE64;
+use base64::Engine;
+use hmac::{Hmac, Mac};
+use sha2::{Digest, Sha256};
+
+type HmacSha256 = Hmac<Sha256>;
+
+/// Pre-computed SCRAM credentials for a user (derived from password).
+#[derive(Debug, Clone)]
+pub struct ScramCredentials {
+    pub salt: Vec<u8>,
+    pub iterations: u32,
+    pub stored_key: Vec<u8>,
+    pub server_key: Vec<u8>,
+}
+
+/// Server-side SCRAM state machine.
+pub struct ScramServer {
+    /// Username extracted from client-first-message.
+    pub username: String,
+    /// Full combined nonce (client + server).
+    combined_nonce: String,
+    /// Server nonce portion (used in tests for verification).
+    #[allow(dead_code)]
+    server_nonce: String,
+    /// Stored credentials (set after TS responds).
+    credentials: Option<ScramCredentials>,
+    /// The server-first-message (for auth message construction).
+    server_first: String,
+    /// The client-first-message-bare (for auth message construction).
+    client_first_bare: String,
+}
+
+impl ScramServer {
+    /// Process the client-first-message.
+    ///
+    /// Parses the client nonce and username, generates a server nonce,
+    /// and returns a partial state that needs credentials to produce the
+    /// server-first-message.
+    pub fn from_client_first(client_first: &str) -> Result<Self, String> {
+        // client-first-message = gs2-header client-first-message-bare
+        // gs2-header = "n,," (no channel binding)
+        // client-first-message-bare = "n=username,r=nonce"
+        let bare = if let Some(rest) = client_first.strip_prefix("n,,") {
+            rest
+        } else if let Some(rest) = client_first.strip_prefix("y,,") {
+            rest
+        } else {
+            return Err("Invalid SCRAM gs2-header".into());
+        };
+
+        let mut username = String::new();
+        let mut client_nonce = String::new();
+
+        for part in bare.split(',') {
+            if let Some(val) = part.strip_prefix("n=") {
+                username = val.to_string();
+            } else if let Some(val) = part.strip_prefix("r=") {
+                client_nonce = val.to_string();
+            }
+        }
+
+        if username.is_empty() || client_nonce.is_empty() {
+            return Err("Missing username or nonce in client-first-message".into());
+        }
+
+        // Generate server nonce
+        let server_nonce: String = (0..24)
+            .map(|_| {
+                let idx = (rand_byte() as usize) % 62;
+                b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"[idx] as char
+            })
+            .collect();
+
+        let combined_nonce = format!("{}{}", client_nonce, server_nonce);
+
+        Ok(ScramServer {
+            username,
+            combined_nonce,
+            server_nonce,
+            credentials: None,
+            server_first: String::new(),
+            client_first_bare: bare.to_string(),
+        })
+    }
+
+    /// Set the credentials and produce the server-first-message.
+    pub fn server_first_message(&mut self, creds: ScramCredentials) -> String {
+        let salt_b64 = BASE64.encode(&creds.salt);
+        let server_first = format!(
+            "r={},s={},i={}",
+            self.combined_nonce, salt_b64, creds.iterations
+        );
+
+        self.server_first = server_first.clone();
+        self.credentials = Some(creds);
+        server_first
+    }
+
+    /// Process the client-final-message and verify the proof.
+    ///
+    /// Returns the server-final-message (containing ServerSignature) on success,
+    /// or an error string on failure.
+    pub fn process_client_final(&mut self, client_final: &str) -> Result<String, String> {
+        let creds = self.credentials.as_ref().ok_or("No credentials set")?;
+
+        // Parse client-final-message
+        // Format: c=biws,r=<combined_nonce>,p=<client_proof>
+        let mut channel_binding = String::new();
+        let mut nonce = String::new();
+        let mut proof_b64 = String::new();
+
+        for part in client_final.split(',') {
+            if let Some(val) = part.strip_prefix("c=") {
+                channel_binding = val.to_string();
+            } else if let Some(val) = part.strip_prefix("r=") {
+                nonce = val.to_string();
+            } else if let Some(val) = part.strip_prefix("p=") {
+                proof_b64 = val.to_string();
+            }
+        }
+
+        // Verify nonce matches
+        if nonce != self.combined_nonce {
+            return Err("Nonce mismatch".into());
+        }
+
+        // Build the client-final-message-without-proof
+        let client_final_without_proof = format!("c={},r={}", channel_binding, nonce);
+
+        // Complete the auth message
+        let auth_message = format!(
+            "{},{},{}",
+            self.client_first_bare, self.server_first, client_final_without_proof
+        );
+
+        // Verify client proof
+        let client_proof = BASE64.decode(proof_b64.as_bytes())
+            .map_err(|_| "Invalid base64 in client proof")?;
+
+        // ClientSignature = HMAC(StoredKey, AuthMessage)
+        let client_signature = hmac_sha256(&creds.stored_key, auth_message.as_bytes());
+
+        // ClientKey = ClientProof XOR ClientSignature
+        if client_proof.len() != client_signature.len() {
+            return Err("Client proof length mismatch".into());
+        }
+        let client_key: Vec<u8> = client_proof
+            .iter()
+            .zip(client_signature.iter())
+            .map(|(a, b)| a ^ b)
+            .collect();
+
+        // StoredKey = H(ClientKey)
+        let computed_stored_key = sha256(&client_key);
+
+        // Verify: computed StoredKey must match the stored StoredKey
+        if computed_stored_key != creds.stored_key {
+            return Err("Authentication failed".into());
+        }
+
+        // Generate ServerSignature for mutual authentication
+        let server_signature = hmac_sha256(&creds.server_key, auth_message.as_bytes());
+        let server_sig_b64 = BASE64.encode(&server_signature);
+
+        Ok(format!("v={}", server_sig_b64))
+    }
+}
+
+/// Compute SCRAM credentials from a plaintext password (for TS to pre-compute).
+pub fn compute_scram_credentials(password: &str, salt: &[u8], iterations: u32) -> ScramCredentials {
+    // SaltedPassword = PBKDF2-HMAC-SHA256(password, salt, iterations)
+    let mut salted_password = [0u8; 32];
+    pbkdf2::pbkdf2_hmac::<Sha256>(
+        password.as_bytes(),
+        salt,
+        iterations,
+        &mut salted_password,
+    );
+
+    // ClientKey = HMAC(SaltedPassword, "Client Key")
+    let client_key = hmac_sha256(&salted_password, b"Client Key");
+
+    // StoredKey = H(ClientKey)
+    let stored_key = sha256(&client_key);
+
+    // ServerKey = HMAC(SaltedPassword, "Server Key")
+    let server_key = hmac_sha256(&salted_password, b"Server Key");
+
+    ScramCredentials {
+        salt: salt.to_vec(),
+        iterations,
+        stored_key,
+        server_key,
+    }
+}
+
+fn hmac_sha256(key: &[u8], data: &[u8]) -> Vec<u8> {
+    let mut mac = HmacSha256::new_from_slice(key).expect("HMAC accepts any key length");
+    mac.update(data);
+    mac.finalize().into_bytes().to_vec()
+}
+
+fn sha256(data: &[u8]) -> Vec<u8> {
+    let mut hasher = Sha256::new();
+    hasher.update(data);
+    hasher.finalize().to_vec()
+}
+
+/// Simple random byte using system randomness.
+fn rand_byte() -> u8 {
+    use std::collections::hash_map::RandomState;
+    use std::hash::{BuildHasher, Hasher};
+    let state = RandomState::new();
+    let mut hasher = state.build_hasher();
+    hasher.write_u64(std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_nanos() as u64);
+    hasher.finish() as u8
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_scram_full_exchange() {
+        let password = "pencil";
+        let salt = b"test-salt-1234";
+        let iterations = 4096;
+
+        // Pre-compute server-side credentials from password
+        let creds = compute_scram_credentials(password, salt, iterations);
+
+        // 1. Client sends client-first-message
+        let client_first = "n,,n=user,r=rOprNGfwEbeRWgbNEkqO";
+        let mut server = ScramServer::from_client_first(client_first).unwrap();
+        assert_eq!(server.username, "user");
+
+        // 2. Server responds with server-first-message
+        let server_first = server.server_first_message(creds.clone());
+        assert!(server_first.starts_with(&format!("r=rOprNGfwEbeRWgbNEkqO{}", server.server_nonce)));
+        assert!(server_first.contains("s="));
+        assert!(server_first.contains("i=4096"));
+
+        // 3. Client computes proof
+        // SaltedPassword
+        let mut salted_password = [0u8; 32];
+        pbkdf2::pbkdf2_hmac::<Sha256>(
+            password.as_bytes(),
+            salt,
+            iterations,
+            &mut salted_password,
+        );
+
+        let client_key = hmac_sha256(&salted_password, b"Client Key");
+        let stored_key = sha256(&client_key);
+
+        let client_first_bare = "n=user,r=rOprNGfwEbeRWgbNEkqO";
+        let client_final_without_proof = format!("c=biws,r={}", server.combined_nonce);
+        let auth_message = format!("{},{},{}", client_first_bare, server_first, client_final_without_proof);
+
+        let client_signature = hmac_sha256(&stored_key, auth_message.as_bytes());
+        let client_proof: Vec<u8> = client_key
+            .iter()
+            .zip(client_signature.iter())
+            .map(|(a, b)| a ^ b)
+            .collect();
+        let proof_b64 = BASE64.encode(&client_proof);
+
+        let client_final = format!("c=biws,r={},p={}", server.combined_nonce, proof_b64);
+
+        // 4. Server verifies proof
+        let result = server.process_client_final(&client_final);
+        assert!(result.is_ok(), "SCRAM verification failed: {:?}", result.err());
+        let server_final = result.unwrap();
+        assert!(server_final.starts_with("v="));
+    }
+
+    #[test]
+    fn test_scram_wrong_password() {
+        let password = "pencil";
+        let wrong_password = "wrong";
+        let salt = b"test-salt";
+        let iterations = 4096;
+
+        let creds = compute_scram_credentials(password, salt, iterations);
+
+        let client_first = "n,,n=user,r=clientnonce123";
+        let mut server = ScramServer::from_client_first(client_first).unwrap();
+        let server_first = server.server_first_message(creds);
+
+        // Client computes proof with wrong password
+        let mut salted_password = [0u8; 32];
+        pbkdf2::pbkdf2_hmac::<Sha256>(
+            wrong_password.as_bytes(),
+            salt,
+            iterations,
+            &mut salted_password,
+        );
+
+        let client_key = hmac_sha256(&salted_password, b"Client Key");
+        let stored_key = sha256(&client_key);
+
+        let client_first_bare = "n=user,r=clientnonce123";
+        let client_final_without_proof = format!("c=biws,r={}", server.combined_nonce);
+        let auth_message = format!("{},{},{}", client_first_bare, server_first, client_final_without_proof);
+
+        let client_signature = hmac_sha256(&stored_key, auth_message.as_bytes());
+        let client_proof: Vec<u8> = client_key
+            .iter()
+            .zip(client_signature.iter())
+            .map(|(a, b)| a ^ b)
+            .collect();
+        let proof_b64 = BASE64.encode(&client_proof);
+
+        let client_final = format!("c=biws,r={},p={}", server.combined_nonce, proof_b64);
+        let result = server.process_client_final(&client_final);
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_compute_scram_credentials() {
+        let creds = compute_scram_credentials("password", b"salt", 4096);
+        assert_eq!(creds.salt, b"salt");
+        assert_eq!(creds.iterations, 4096);
+        assert_eq!(creds.stored_key.len(), 32);
+        assert_eq!(creds.server_key.len(), 32);
+    }
+
+    #[test]
+    fn test_invalid_client_first() {
+        assert!(ScramServer::from_client_first("invalid").is_err());
+        assert!(ScramServer::from_client_first("n,,").is_err());
+    }
+}

rust/crates/mailer-smtp/src/server.rs

@@ -12,6 +12,7 @@ use crate::rate_limiter::{RateLimitConfig, RateLimiter};
 use hickory_resolver::TokioResolver;
 use mailer_security::MessageAuthenticator;
 use rustls_pki_types::{CertificateDer, PrivateKeyDer};
+use std::collections::HashMap;
 use std::io::BufReader;
 use std::sync::atomic::{AtomicBool, AtomicU32, Ordering};
 use std::sync::Arc;
@@ -263,6 +264,69 @@ async fn accept_loop(
     }
 }
 
+/// SNI-based certificate resolver that selects the appropriate TLS certificate
+/// based on the client's requested hostname.
+struct SniCertResolver {
+    /// Domain -> certified key mapping.
+    certs: HashMap<String, Arc<rustls::sign::CertifiedKey>>,
+    /// Default certificate for non-matching SNI or missing SNI.
+    default: Arc<rustls::sign::CertifiedKey>,
+}
+
+impl std::fmt::Debug for SniCertResolver {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("SniCertResolver")
+            .field("domains", &self.certs.keys().collect::<Vec<_>>())
+            .finish()
+    }
+}
+
+impl rustls::server::ResolvesServerCert for SniCertResolver {
+    fn resolve(
+        &self,
+        client_hello: rustls::server::ClientHello<'_>,
+    ) -> Option<Arc<rustls::sign::CertifiedKey>> {
+        if let Some(sni) = client_hello.server_name() {
+            let sni_lower = sni.to_lowercase();
+            if let Some(key) = self.certs.get(&sni_lower) {
+                return Some(key.clone());
+            }
+        }
+        Some(self.default.clone())
+    }
+}
+
+/// Parse a PEM cert+key pair into a `CertifiedKey`.
+fn parse_certified_key(
+    cert_pem: &str,
+    key_pem: &str,
+) -> Result<rustls::sign::CertifiedKey, Box<dyn std::error::Error + Send + Sync>> {
+    let certs: Vec<CertificateDer<'static>> = {
+        let mut reader = BufReader::new(cert_pem.as_bytes());
+        rustls_pemfile::certs(&mut reader).collect::<Result<Vec<_>, _>>()?
+    };
+    if certs.is_empty() {
+        return Err("No certificates found in PEM".into());
+    }
+
+    let key: PrivateKeyDer<'static> = {
+        let mut reader = BufReader::new(key_pem.as_bytes());
+        let mut keys = Vec::new();
+        for item in rustls_pemfile::read_all(&mut reader) {
+            match item? {
+                rustls_pemfile::Item::Pkcs8Key(key) => keys.push(PrivateKeyDer::Pkcs8(key)),
+                rustls_pemfile::Item::Pkcs1Key(key) => keys.push(PrivateKeyDer::Pkcs1(key)),
+                rustls_pemfile::Item::Sec1Key(key) => keys.push(PrivateKeyDer::Sec1(key)),
+                _ => {}
+            }
+        }
+        keys.into_iter().next().ok_or("No private key found in PEM")?
+    };
+
+    let signing_key = rustls::crypto::ring::sign::any_supported_type(&key)?;
+    Ok(rustls::sign::CertifiedKey::new(certs, signing_key))
+}
+
 /// Build a TLS acceptor from PEM cert/key strings.
 fn build_tls_acceptor(
     config: &SmtpServerConfig,
@@ -311,9 +375,42 @@ fn build_tls_acceptor(
             .ok_or("No private key found in PEM")?
     };
 
-    let tls_config = rustls::ServerConfig::builder()
+    // If additional TLS certs are configured, use SNI-based resolution
+    let tls_config = if config.additional_tls_certs.is_empty() {
+        rustls::ServerConfig::builder()
             .with_no_client_auth()
-        .with_single_cert(certs, key)?;
+            .with_single_cert(certs, key)?
+    } else {
+        // Build default certified key
+        let signing_key = rustls::crypto::ring::sign::any_supported_type(&key)?;
+        let default_ck = Arc::new(rustls::sign::CertifiedKey::new(certs, signing_key));
+
+        // Build per-domain certs
+        let mut domain_certs = HashMap::new();
+        for domain_cert in &config.additional_tls_certs {
+            match parse_certified_key(&domain_cert.cert_pem, &domain_cert.key_pem) {
+                Ok(ck) => {
+                    let ck = Arc::new(ck);
+                    for domain in &domain_cert.domains {
+                        domain_certs.insert(domain.to_lowercase(), ck.clone());
+                    }
+                    info!("SNI cert loaded for domains: {:?}", domain_cert.domains);
+                }
+                Err(e) => {
+                    warn!("Failed to load SNI cert for domains {:?}: {}", domain_cert.domains, e);
+                }
+            }
+        }
+
+        let resolver = SniCertResolver {
+            certs: domain_certs,
+            default: default_ck,
+        };
+
+        rustls::ServerConfig::builder()
+            .with_no_client_auth()
+            .with_cert_resolver(Arc::new(resolver))
+    };
 
     Ok(tokio_rustls::TlsAcceptor::from(Arc::new(tls_config)))
 }

test/test.emailauth.ts

@@ -1,10 +1,8 @@
 import { tap, expect } from '@git.zone/tstest/tapbundle';
 import { SpfVerifier, SpfQualifier, SpfMechanismType } from '../ts/mail/security/classes.spfverifier.js';
-import { DmarcVerifier, DmarcPolicy, DmarcAlignment } from '../ts/mail/security/classes.dmarcverifier.js';
-import { Email } from '../ts/mail/core/classes.email.js';
 
 /**
- * Test email authentication systems: SPF and DMARC
+ * Test email authentication systems: SPF parsing
  */
 
 // SPF Verifier Tests
@@ -41,153 +39,6 @@ tap.test('SPF Verifier - should parse SPF record', async () => {
   expect(invalidParsed).toBeNull();
 });
 
-// DMARC Verifier Tests
-tap.test('DMARC Verifier - should parse DMARC record', async () => {
-  const dmarcVerifier = new DmarcVerifier();
-  
-  // Test valid DMARC record parsing
-  const record = 'v=DMARC1; p=reject; sp=quarantine; pct=50; adkim=s; aspf=r; rua=mailto:dmarc@example.com';
-  const parsedRecord = dmarcVerifier.parseDmarcRecord(record);
-  
-  expect(parsedRecord).toBeTruthy();
-  expect(parsedRecord.version).toEqual('DMARC1');
-  expect(parsedRecord.policy).toEqual(DmarcPolicy.REJECT);
-  expect(parsedRecord.subdomainPolicy).toEqual(DmarcPolicy.QUARANTINE);
-  expect(parsedRecord.pct).toEqual(50);
-  expect(parsedRecord.adkim).toEqual(DmarcAlignment.STRICT);
-  expect(parsedRecord.aspf).toEqual(DmarcAlignment.RELAXED);
-  expect(parsedRecord.reportUriAggregate).toContain('dmarc@example.com');
-  
-  // Test invalid record
-  const invalidRecord = 'not-a-dmarc-record';
-  const invalidParsed = dmarcVerifier.parseDmarcRecord(invalidRecord);
-  expect(invalidParsed).toBeNull();
-});
-
-tap.test('DMARC Verifier - should verify DMARC alignment', async () => {
-  const dmarcVerifier = new DmarcVerifier();
-  
-  // Test email domains with DMARC alignment
-  const email = new Email({
-    from: 'sender@example.com',
-    to: 'recipient@example.net',
-    subject: 'Test DMARC alignment',
-    text: 'This is a test email'
-  });
-  
-  // Test when both SPF and DKIM pass with alignment
-  const dmarcResult = await dmarcVerifier.verify(
-    email,
-    { domain: 'example.com', result: true },  // SPF - aligned and passed
-    { domain: 'example.com', result: true }   // DKIM - aligned and passed
-  );
-  
-  expect(dmarcResult).toBeTruthy();
-  expect(dmarcResult.spfPassed).toEqual(true);
-  expect(dmarcResult.dkimPassed).toEqual(true);
-  expect(dmarcResult.spfDomainAligned).toEqual(true);
-  expect(dmarcResult.dkimDomainAligned).toEqual(true);
-  expect(dmarcResult.action).toEqual('pass');
-  
-  // Test when neither SPF nor DKIM is aligned
-  const dmarcResult2 = await dmarcVerifier.verify(
-    email,
-    { domain: 'differentdomain.com', result: true },  // SPF - passed but not aligned
-    { domain: 'anotherdomain.com', result: true }     // DKIM - passed but not aligned
-  );
-  
-  // Without a DNS manager, no DMARC record will be found
-  
-  expect(dmarcResult2).toBeTruthy();
-  expect(dmarcResult2.spfPassed).toEqual(true);
-  expect(dmarcResult2.dkimPassed).toEqual(true);
-  expect(dmarcResult2.spfDomainAligned).toEqual(false);
-  expect(dmarcResult2.dkimDomainAligned).toEqual(false);
-  
-  // Without a DMARC record, the default action is 'pass'
-  expect(dmarcResult2.hasDmarc).toEqual(false);
-  expect(dmarcResult2.policyEvaluated).toEqual(DmarcPolicy.NONE);
-  expect(dmarcResult2.actualPolicy).toEqual(DmarcPolicy.NONE);
-  expect(dmarcResult2.action).toEqual('pass');
-});
-
-tap.test('DMARC Verifier - should apply policy correctly', async () => {
-  const dmarcVerifier = new DmarcVerifier();
-  
-  // Create test email
-  const email = new Email({
-    from: 'sender@example.com',
-    to: 'recipient@example.net',
-    subject: 'Test DMARC policy application',
-    text: 'This is a test email'
-  });
-  
-  // Test pass action
-  const passResult: any = {
-    hasDmarc: true,
-    spfDomainAligned: true,
-    dkimDomainAligned: true,
-    spfPassed: true,
-    dkimPassed: true,
-    policyEvaluated: DmarcPolicy.NONE,
-    actualPolicy: DmarcPolicy.NONE,
-    appliedPercentage: 100,
-    action: 'pass',
-    details: 'DMARC passed'
-  };
-  
-  const passApplied = dmarcVerifier.applyPolicy(email, passResult);
-  expect(passApplied).toEqual(true);
-  expect(email.mightBeSpam).toEqual(false);
-  expect(email.headers['X-DMARC-Result']).toEqual('DMARC passed');
-  
-  // Test quarantine action
-  const quarantineResult: any = {
-    hasDmarc: true,
-    spfDomainAligned: false,
-    dkimDomainAligned: false,
-    spfPassed: false,
-    dkimPassed: false,
-    policyEvaluated: DmarcPolicy.QUARANTINE,
-    actualPolicy: DmarcPolicy.QUARANTINE,
-    appliedPercentage: 100,
-    action: 'quarantine',
-    details: 'DMARC failed, policy=quarantine'
-  };
-  
-  // Reset email spam flag
-  email.mightBeSpam = false;
-  email.headers = {};
-  
-  const quarantineApplied = dmarcVerifier.applyPolicy(email, quarantineResult);
-  expect(quarantineApplied).toEqual(true);
-  expect(email.mightBeSpam).toEqual(true);
-  expect(email.headers['X-Spam-Flag']).toEqual('YES');
-  expect(email.headers['X-DMARC-Result']).toEqual('DMARC failed, policy=quarantine');
-  
-  // Test reject action
-  const rejectResult: any = {
-    hasDmarc: true,
-    spfDomainAligned: false,
-    dkimDomainAligned: false,
-    spfPassed: false,
-    dkimPassed: false,
-    policyEvaluated: DmarcPolicy.REJECT,
-    actualPolicy: DmarcPolicy.REJECT,
-    appliedPercentage: 100,
-    action: 'reject',
-    details: 'DMARC failed, policy=reject'
-  };
-  
-  // Reset email spam flag
-  email.mightBeSpam = false;
-  email.headers = {};
-  
-  const rejectApplied = dmarcVerifier.applyPolicy(email, rejectResult);
-  expect(rejectApplied).toEqual(false);
-  expect(email.mightBeSpam).toEqual(true);
-});
-
 tap.test('stop', async () => {
   await tap.stopForcefully();
 });

test/test.mta.delivery.node.ts

@@ -0,0 +1,295 @@
+import { tap, expect } from '@git.zone/tstest/tapbundle';
+import { UnifiedEmailServer } from '../ts/mail/routing/classes.unified.email.server.js';
+import { RustSecurityBridge } from '../ts/security/classes.rustsecuritybridge.js';
+import { Email } from '../ts/mail/core/classes.email.js';
+import * as net from 'net';
+import * as dns from 'dns';
+
+const storageMap = new Map<string, string>();
+const mockDcRouter = {
+  storageManager: {
+    get: async (key: string) => storageMap.get(key) || null,
+    set: async (key: string, value: string) => { storageMap.set(key, value); },
+  },
+};
+
+let server: UnifiedEmailServer;
+let bridgeAvailable = false;
+let mockSmtpServer: net.Server;
+
+/**
+ * Create a minimal mock SMTP server that accepts any email.
+ */
+function createMockSmtpServer(port: number): Promise<net.Server> {
+  return new Promise((resolve, reject) => {
+    const srv = net.createServer((socket) => {
+      socket.write('220 mock-smtp.local ESMTP MockServer\r\n');
+
+      let inData = false;
+      let dataBuffer = '';
+
+      socket.on('data', (chunk) => {
+        const input = chunk.toString();
+
+        if (inData) {
+          dataBuffer += input;
+          if (dataBuffer.includes('\r\n.\r\n')) {
+            inData = false;
+            dataBuffer = '';
+            socket.write('250 2.0.0 Ok: queued\r\n');
+          }
+          return;
+        }
+
+        const lines = input.split('\r\n').filter((l: string) => l.length > 0);
+        for (const line of lines) {
+          const cmd = line.toUpperCase();
+          if (cmd.startsWith('EHLO') || cmd.startsWith('HELO')) {
+            socket.write(`250-mock-smtp.local\r\n250-SIZE 10485760\r\n250 OK\r\n`);
+          } else if (cmd.startsWith('MAIL FROM')) {
+            socket.write('250 2.1.0 Ok\r\n');
+          } else if (cmd.startsWith('RCPT TO')) {
+            socket.write('250 2.1.5 Ok\r\n');
+          } else if (cmd === 'DATA') {
+            inData = true;
+            dataBuffer = '';
+            socket.write('354 End data with <CR><LF>.<CR><LF>\r\n');
+          } else if (cmd === 'QUIT') {
+            socket.write('221 2.0.0 Bye\r\n');
+            socket.end();
+          } else if (cmd === 'RSET') {
+            socket.write('250 2.0.0 Ok\r\n');
+          }
+        }
+      });
+    });
+
+    srv.listen(port, '127.0.0.1', () => {
+      resolve(srv);
+    });
+
+    srv.on('error', reject);
+  });
+}
+
+// Store original resolveMx so we can restore it
+const originalResolveMx = dns.promises.Resolver.prototype.resolveMx;
+
+tap.test('setup - start server and mock SMTP', async () => {
+  RustSecurityBridge.resetInstance();
+
+  server = new UnifiedEmailServer(mockDcRouter, {
+    ports: [10425],
+    hostname: 'test.mta.local',
+    domains: [
+      { domain: 'mta-test.com', dnsMode: 'forward' },
+    ],
+    routes: [
+      {
+        name: 'mta-route',
+        priority: 10,
+        match: { recipients: '*@mta-test.com' },
+        action: { type: 'deliver' },
+      },
+      {
+        name: 'process-route',
+        priority: 20,
+        match: { recipients: '*@process-test.com' },
+        action: {
+          type: 'process',
+          options: {
+            contentScanning: true,
+            scanners: [{ type: 'spam' }],
+          },
+        },
+      },
+    ],
+  });
+
+  try {
+    await server.start();
+    bridgeAvailable = true;
+  } catch (err) {
+    console.log(`SKIP: Server failed to start — ${(err as Error).message}`);
+    console.log('Build the Rust binary with: cd rust && cargo build --release');
+    return;
+  }
+
+  mockSmtpServer = await createMockSmtpServer(10426);
+});
+
+tap.test('MX resolution for a public domain', async () => {
+  if (!bridgeAvailable) { console.log('SKIP'); return; }
+
+  // Use the delivery system's resolveMxForDomain via a quick DNS lookup
+  const resolver = new dns.promises.Resolver();
+  try {
+    const records = await resolver.resolveMx('gmail.com');
+    expect(records).toBeTruthy();
+    expect(records.length).toBeGreaterThan(0);
+    // Each record should have exchange and priority
+    for (const rec of records) {
+      expect(typeof rec.exchange).toEqual('string');
+      expect(typeof rec.priority).toEqual('number');
+    }
+    console.log(`Resolved ${records.length} MX records for gmail.com`);
+  } catch (err) {
+    console.log(`SKIP: DNS resolution failed (network may be unavailable): ${(err as Error).message}`);
+  }
+});
+
+tap.test('group recipients by domain', async () => {
+  if (!bridgeAvailable) { console.log('SKIP'); return; }
+
+  // Test the grouping logic directly
+  const recipients = [
+    'alice@example.com',
+    'bob@example.com',
+    'carol@other.org',
+    'dave@example.com',
+    'eve@other.org',
+  ];
+
+  const groups = new Map<string, string[]>();
+  for (const rcpt of recipients) {
+    const domain = rcpt.split('@')[1]?.toLowerCase();
+    if (!domain) continue;
+    const list = groups.get(domain) || [];
+    list.push(rcpt);
+    groups.set(domain, list);
+  }
+
+  expect(groups.size).toEqual(2);
+  expect(groups.get('example.com')!.length).toEqual(3);
+  expect(groups.get('other.org')!.length).toEqual(2);
+});
+
+tap.test('MTA delivery to mock SMTP server via mocked MX', async () => {
+  if (!bridgeAvailable) { console.log('SKIP'); return; }
+
+  // Mock dns.promises.Resolver.resolveMx to return 127.0.0.1
+  dns.promises.Resolver.prototype.resolveMx = async function (_hostname: string) {
+    return [{ exchange: '127.0.0.1', priority: 10 }];
+  };
+
+  const email = new Email({
+    from: 'sender@mta-test.com',
+    to: 'recipient@target-domain.com',
+    subject: 'MTA Delivery Test',
+    text: 'Testing MTA delivery with MX resolution.',
+  });
+
+  // Use sendOutboundEmail at the resolved MX host (which is mocked to 127.0.0.1)
+  // But the real test is the delivery system's handleMtaDelivery, which we test
+  // by sending through the server's outbound path with the mock MX.
+
+  // Direct test: resolve MX then send
+  const resolver = new dns.promises.Resolver();
+  const mxRecords = await resolver.resolveMx('target-domain.com');
+  expect(mxRecords[0].exchange).toEqual('127.0.0.1');
+
+  // Send via the resolved MX host to the mock SMTP server on port 10425
+  // Note: MTA delivery uses port 25 by default, but our mock is on 10425.
+  // We test the sendOutboundEmail path directly with the mock MX host.
+  const result = await server.sendOutboundEmail('127.0.0.1', 10426, email);
+  expect(result).toBeTruthy();
+  expect(result.accepted.length).toBeGreaterThan(0);
+  expect(result.response).toInclude('2.0.0');
+
+  // Restore original resolveMx
+  dns.promises.Resolver.prototype.resolveMx = originalResolveMx;
+});
+
+tap.test('MTA delivery - connection refused to unreachable MX', async () => {
+  if (!bridgeAvailable) { console.log('SKIP'); return; }
+
+  const email = new Email({
+    from: 'sender@mta-test.com',
+    to: 'recipient@unreachable-domain.com',
+    subject: 'Connection Refused MX Test',
+    text: 'This should fail — no server at the target.',
+  });
+
+  // Send to a port that nothing is listening on
+  try {
+    await server.sendOutboundEmail('127.0.0.1', 59789, email);
+    throw new Error('Expected sendOutboundEmail to fail');
+  } catch (err: any) {
+    expect(err).toBeTruthy();
+    expect(err.message.length).toBeGreaterThan(0);
+    console.log(`Got expected error: ${err.message}`);
+  }
+});
+
+tap.test('MTA delivery with multiple recipients across domains', async () => {
+  if (!bridgeAvailable) { console.log('SKIP'); return; }
+
+  // Mock MX to return 127.0.0.1 for all domains
+  dns.promises.Resolver.prototype.resolveMx = async function (_hostname: string) {
+    return [{ exchange: '127.0.0.1', priority: 10 }];
+  };
+
+  const email = new Email({
+    from: 'sender@mta-test.com',
+    to: ['alice@domain-a.com', 'bob@domain-b.com'],
+    subject: 'Multi-Domain MTA Test',
+    text: 'Testing delivery to multiple domains.',
+  });
+
+  // Send to each recipient's domain individually (simulating MTA behavior)
+  for (const recipient of email.to) {
+    const singleEmail = new Email({
+      from: email.from,
+      to: recipient,
+      subject: email.subject,
+      text: email.text,
+    });
+    const result = await server.sendOutboundEmail('127.0.0.1', 10426, singleEmail);
+    expect(result.accepted.length).toEqual(1);
+  }
+
+  // Restore original resolveMx
+  dns.promises.Resolver.prototype.resolveMx = originalResolveMx;
+});
+
+tap.test('E2E: send real email to hello@task.vc via MX resolution', async () => {
+  if (!bridgeAvailable) { console.log('SKIP'); return; }
+
+  // Resolve real MX records for task.vc
+  const resolver = new dns.promises.Resolver();
+  const mxRecords = await resolver.resolveMx('task.vc');
+  expect(mxRecords.length).toBeGreaterThan(0);
+  const mxHost = mxRecords.sort((a, b) => a.priority - b.priority)[0].exchange;
+  console.log(`Resolved MX for task.vc: ${mxHost} (priority ${mxRecords[0].priority})`);
+
+  const email = new Email({
+    from: 'test@mta-test.com',
+    to: 'hello@task.vc',
+    subject: `MTA E2E Test — ${new Date().toISOString()}`,
+    text: 'This is an automated E2E test from @serve.zone/mailer verifying real MX resolution and outbound SMTP delivery.',
+  });
+
+  const result = await server.sendOutboundEmail(mxHost, 25, email);
+  expect(result).toBeTruthy();
+  expect(result.accepted).toBeTruthy();
+  expect(result.accepted.length).toEqual(1);
+  expect(result.accepted[0]).toEqual('hello@task.vc');
+  expect(result.response).toInclude('2.0.0');
+  console.log(`Email delivered to hello@task.vc via ${mxHost}: ${result.response}`);
+});
+
+tap.test('cleanup - stop server and mock SMTP', async () => {
+  // Restore MX resolver in case it wasn't restored
+  dns.promises.Resolver.prototype.resolveMx = originalResolveMx;
+
+  // Force-close mock server (destroy all open sockets)
+  if (mockSmtpServer) {
+    mockSmtpServer.close();
+  }
+  if (bridgeAvailable) {
+    await server.stop();
+  }
+  await tap.stopForcefully();
+});
+
+export default tap.start();

test/test.ratelimiter.ts

@@ -1,141 +0,0 @@
-import { tap, expect } from '@git.zone/tstest/tapbundle';
-import { RateLimiter } from '../ts/mail/delivery/classes.ratelimiter.js';
-
-tap.test('RateLimiter - should be instantiable', async () => {
-  const limiter = new RateLimiter({
-    maxPerPeriod: 10,
-    periodMs: 1000,
-    perKey: true
-  });
-  
-  expect(limiter).toBeTruthy();
-});
-
-tap.test('RateLimiter - should allow requests within rate limit', async () => {
-  const limiter = new RateLimiter({
-    maxPerPeriod: 5,
-    periodMs: 1000,
-    perKey: true
-  });
-  
-  // Should allow 5 requests
-  for (let i = 0; i < 5; i++) {
-    expect(limiter.isAllowed('test')).toEqual(true);
-  }
-  
-  // 6th request should be denied
-  expect(limiter.isAllowed('test')).toEqual(false);
-});
-
-tap.test('RateLimiter - should enforce per-key limits', async () => {
-  const limiter = new RateLimiter({
-    maxPerPeriod: 3,
-    periodMs: 1000,
-    perKey: true
-  });
-  
-  // Should allow 3 requests for key1
-  for (let i = 0; i < 3; i++) {
-    expect(limiter.isAllowed('key1')).toEqual(true);
-  }
-  
-  // 4th request for key1 should be denied
-  expect(limiter.isAllowed('key1')).toEqual(false);
-  
-  // But key2 should still be allowed
-  expect(limiter.isAllowed('key2')).toEqual(true);
-});
-
-tap.test('RateLimiter - should refill tokens over time', async () => {
-  const limiter = new RateLimiter({
-    maxPerPeriod: 2,
-    periodMs: 100, // Short period for testing
-    perKey: true
-  });
-  
-  // Use all tokens
-  expect(limiter.isAllowed('test')).toEqual(true);
-  expect(limiter.isAllowed('test')).toEqual(true);
-  expect(limiter.isAllowed('test')).toEqual(false);
-  
-  // Wait for refill
-  await new Promise(resolve => setTimeout(resolve, 150));
-  
-  // Should have tokens again
-  expect(limiter.isAllowed('test')).toEqual(true);
-});
-
-tap.test('RateLimiter - should support burst allowance', async () => {
-  const limiter = new RateLimiter({
-    maxPerPeriod: 2,
-    periodMs: 100,
-    perKey: true,
-    burstTokens: 2, // Allow 2 extra tokens for bursts
-    initialTokens: 4  // Start with max + burst tokens
-  });
-  
-  // Should allow 4 requests (2 regular + 2 burst)
-  for (let i = 0; i < 4; i++) {
-    expect(limiter.isAllowed('test')).toEqual(true);
-  }
-  
-  // 5th request should be denied
-  expect(limiter.isAllowed('test')).toEqual(false);
-  
-  // Wait for refill
-  await new Promise(resolve => setTimeout(resolve, 150));
-  
-  // Should have 2 tokens again (rate-limited to normal max, not burst)
-  expect(limiter.isAllowed('test')).toEqual(true);
-  expect(limiter.isAllowed('test')).toEqual(true);
-  
-  // 3rd request after refill should fail (only normal max is refilled, not burst)
-  expect(limiter.isAllowed('test')).toEqual(false);
-});
-
-tap.test('RateLimiter - should return correct stats', async () => {
-  const limiter = new RateLimiter({
-    maxPerPeriod: 10,
-    periodMs: 1000,
-    perKey: true
-  });
-  
-  // Make some requests
-  limiter.isAllowed('test');
-  limiter.isAllowed('test');
-  limiter.isAllowed('test');
-  
-  // Get stats
-  const stats = limiter.getStats('test');
-  
-  expect(stats.remaining).toEqual(7);
-  expect(stats.limit).toEqual(10);
-  expect(stats.allowed).toEqual(3);
-  expect(stats.denied).toEqual(0);
-});
-
-tap.test('RateLimiter - should reset limits', async () => {
-  const limiter = new RateLimiter({
-    maxPerPeriod: 3,
-    periodMs: 1000,
-    perKey: true
-  });
-  
-  // Use all tokens
-  expect(limiter.isAllowed('test')).toEqual(true);
-  expect(limiter.isAllowed('test')).toEqual(true);
-  expect(limiter.isAllowed('test')).toEqual(true);
-  expect(limiter.isAllowed('test')).toEqual(false);
-  
-  // Reset
-  limiter.reset('test');
-  
-  // Should have tokens again
-  expect(limiter.isAllowed('test')).toEqual(true);
-});
-
-tap.test('stop', async () => {
-  await tap.stopForcefully();
-});
-
-export default tap.start();

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartmta',
-  version: '4.1.1',
+  version: '5.1.3',
   description: 'A high-performance, enterprise-grade Mail Transfer Agent (MTA) built from scratch in TypeScript with Rust acceleration.'
 }

ts/errors/index.ts

@@ -1,119 +0,0 @@
-/**
- * MTA error classes for SMTP client operations
- */
-
-export class MtaConnectionError extends Error {
-  public code: string;
-  public details?: any;
-  constructor(message: string, detailsOrCode?: any) {
-    super(message);
-    this.name = 'MtaConnectionError';
-    if (typeof detailsOrCode === 'string') {
-      this.code = detailsOrCode;
-    } else {
-      this.code = 'CONNECTION_ERROR';
-      this.details = detailsOrCode;
-    }
-  }
-  static timeout(host: string, port: number, timeoutMs?: number): MtaConnectionError {
-    return new MtaConnectionError(`Connection to ${host}:${port} timed out${timeoutMs ? ` after ${timeoutMs}ms` : ''}`, 'TIMEOUT');
-  }
-  static refused(host: string, port: number): MtaConnectionError {
-    return new MtaConnectionError(`Connection to ${host}:${port} refused`, 'REFUSED');
-  }
-  static dnsError(host: string, err?: any): MtaConnectionError {
-    const errMsg = typeof err === 'string' ? err : err?.message || '';
-    return new MtaConnectionError(`DNS resolution failed for ${host}${errMsg ? `: ${errMsg}` : ''}`, 'DNS_ERROR');
-  }
-}
-
-export class MtaAuthenticationError extends Error {
-  public code: string;
-  public details?: any;
-  constructor(message: string, detailsOrCode?: any) {
-    super(message);
-    this.name = 'MtaAuthenticationError';
-    if (typeof detailsOrCode === 'string') {
-      this.code = detailsOrCode;
-    } else {
-      this.code = 'AUTH_ERROR';
-      this.details = detailsOrCode;
-    }
-  }
-  static invalidCredentials(host?: string, user?: string): MtaAuthenticationError {
-    const detail = host && user ? `${user}@${host}` : host || user || '';
-    return new MtaAuthenticationError(`Authentication failed${detail ? `: ${detail}` : ''}`, 'INVALID_CREDENTIALS');
-  }
-}
-
-export class MtaDeliveryError extends Error {
-  public code: string;
-  public responseCode?: number;
-  public details?: any;
-  constructor(message: string, detailsOrCode?: any, responseCode?: number) {
-    super(message);
-    this.name = 'MtaDeliveryError';
-    if (typeof detailsOrCode === 'string') {
-      this.code = detailsOrCode;
-      this.responseCode = responseCode;
-    } else {
-      this.code = 'DELIVERY_ERROR';
-      this.details = detailsOrCode;
-    }
-  }
-  static temporary(message: string, ...args: any[]): MtaDeliveryError {
-    return new MtaDeliveryError(message, 'TEMPORARY');
-  }
-  static permanent(message: string, ...args: any[]): MtaDeliveryError {
-    return new MtaDeliveryError(message, 'PERMANENT');
-  }
-}
-
-export class MtaConfigurationError extends Error {
-  public code: string;
-  public details?: any;
-  constructor(message: string, detailsOrCode?: any) {
-    super(message);
-    this.name = 'MtaConfigurationError';
-    if (typeof detailsOrCode === 'string') {
-      this.code = detailsOrCode;
-    } else {
-      this.code = 'CONFIG_ERROR';
-      this.details = detailsOrCode;
-    }
-  }
-}
-
-export class MtaTimeoutError extends Error {
-  public code: string;
-  public details?: any;
-  constructor(message: string, detailsOrCode?: any) {
-    super(message);
-    this.name = 'MtaTimeoutError';
-    if (typeof detailsOrCode === 'string') {
-      this.code = detailsOrCode;
-    } else {
-      this.code = 'TIMEOUT';
-      this.details = detailsOrCode;
-    }
-  }
-  static commandTimeout(command: string, hostOrTimeout?: any, timeoutMs?: number): MtaTimeoutError {
-    const timeout = typeof hostOrTimeout === 'number' ? hostOrTimeout : timeoutMs;
-    return new MtaTimeoutError(`Command '${command}' timed out${timeout ? ` after ${timeout}ms` : ''}`, 'COMMAND_TIMEOUT');
-  }
-}
-
-export class MtaProtocolError extends Error {
-  public code: string;
-  public details?: any;
-  constructor(message: string, detailsOrCode?: any) {
-    super(message);
-    this.name = 'MtaProtocolError';
-    if (typeof detailsOrCode === 'string') {
-      this.code = detailsOrCode;
-    } else {
-      this.code = 'PROTOCOL_ERROR';
-      this.details = detailsOrCode;
-    }
-  }
-}

ts/mail/delivery/classes.delivery.queue.ts

@@ -3,7 +3,7 @@ import { EventEmitter } from 'node:events';
 import * as fs from 'node:fs';
 import * as path from 'node:path';
 import { logger } from '../../logger.js';
-import { type EmailProcessingMode } from '../routing/classes.email.config.js';
+import { type EmailProcessingMode } from './interfaces.js';
 import type { IEmailRoute } from '../routing/interfaces.js';
 
 /**

ts/mail/delivery/classes.delivery.system.ts

@@ -7,10 +7,12 @@ import {
   SecurityEventType
 } from '../../security/index.js';
 import { UnifiedDeliveryQueue, type IQueueItem } from './classes.delivery.queue.js';
-import type { Email } from '../core/classes.email.js';
+import { Email } from '../core/classes.email.js';
 import type { UnifiedEmailServer } from '../routing/classes.unified.email.server.js';
 import { RustSecurityBridge } from '../../security/classes.rustsecuritybridge.js';
 
+const dns = plugins.dns;
+
 /**
  * Delivery status enumeration
  */
@@ -480,6 +482,36 @@ export class MultiModeDeliverySystem extends EventEmitter {
     }
   }
   
+  /**
+   * Resolve MX records for a domain, sorted by priority (lowest first).
+   * Falls back to the domain itself as an A record per RFC 5321.
+   */
+  private async resolveMxForDomain(domain: string): Promise<Array<{ exchange: string; priority: number }>> {
+    const resolver = new dns.promises.Resolver();
+    try {
+      const mxRecords = await resolver.resolveMx(domain);
+      return mxRecords.sort((a, b) => a.priority - b.priority);
+    } catch (err) {
+      logger.log('warn', `No MX records for ${domain}, falling back to A record`);
+      return [{ exchange: domain, priority: 0 }];
+    }
+  }
+
+  /**
+   * Group recipient addresses by their domain part.
+   */
+  private groupRecipientsByDomain(recipients: string[]): Map<string, string[]> {
+    const groups = new Map<string, string[]>();
+    for (const rcpt of recipients) {
+      const domain = rcpt.split('@')[1]?.toLowerCase();
+      if (!domain) continue;
+      const list = groups.get(domain) || [];
+      list.push(rcpt);
+      groups.set(domain, list);
+    }
+    return groups;
+  }
+
   /**
    * Default handler for MTA mode delivery
    * @param item Queue item
@@ -488,33 +520,83 @@ export class MultiModeDeliverySystem extends EventEmitter {
     logger.log('info', `MTA delivery for item ${item.id}`);
 
     const email = item.processingResult as Email;
-    const route = item.route;
 
+    if (!this.emailServer) {
+      throw new Error('No email server available for MTA delivery');
+    }
+
+    // Build DKIM options from route config
+    const dkimDomain = item.route?.action.options?.mtaOptions?.dkimSign
+      ? (item.route.action.options.mtaOptions.dkimOptions?.domainName || email.from.split('@')[1])
+      : undefined;
+    const dkimSelector = item.route?.action.options?.mtaOptions?.dkimOptions?.keySelector || 'default';
+
+    const allRecipients = email.getAllRecipients();
+    if (allRecipients.length === 0) {
+      throw new Error('No recipients specified for MTA delivery');
+    }
+
+    const domainGroups = this.groupRecipientsByDomain(allRecipients);
+    const results: Array<{ domain: string; success: boolean; error?: string; accepted?: string[]; rejected?: string[] }> = [];
+
+    for (const [domain, recipients] of domainGroups) {
+      const mxHosts = await this.resolveMxForDomain(domain);
+      let delivered = false;
+      let lastError: string | undefined;
+
+      for (const mx of mxHosts) {
         try {
-      // Apply DKIM signing if configured in the route
-      if (item.route?.action.options?.mtaOptions?.dkimSign) {
-        await this.applyDkimSigning(email, item.route.action.options.mtaOptions);
-      }
+          logger.log('info', `MTA: trying MX ${mx.exchange}:25 for domain ${domain} (priority ${mx.priority})`);
 
-      // In a full implementation, this would use the MTA service
-      // For now, we'll simulate a successful delivery
-      
-      logger.log('info', `Email processed by MTA: ${email.subject} to ${email.getAllRecipients().join(', ')}`);
-      
-      // Note: The MTA implementation would handle actual local delivery
-      
-      // Simulate successful delivery
-      return {
-        recipients: email.getAllRecipients().length,
+          // Create a temporary Email scoped to this domain's recipients
+          const domainEmail = new Email({
+            from: email.from,
+            to: recipients.filter(r => email.to.includes(r)),
+            cc: recipients.filter(r => (email.cc || []).includes(r)),
+            bcc: recipients.filter(r => (email.bcc || []).includes(r)),
             subject: email.subject,
-        dkimSigned: !!item.route?.action.options?.mtaOptions?.dkimSign
-      };
-    } catch (error: any) {
-      logger.log('error', `Failed to process email in MTA mode: ${error.message}`);
-      throw error;
+            text: email.text,
+            html: email.html,
+          });
+
+          const result = await this.emailServer.sendOutboundEmail(mx.exchange, 25, domainEmail, {
+            dkimDomain,
+            dkimSelector,
+          });
+
+          results.push({
+            domain,
+            success: true,
+            accepted: result.accepted,
+            rejected: result.rejected,
+          });
+          delivered = true;
+          logger.log('info', `MTA: delivered to ${domain} via ${mx.exchange}`);
+          break;
+        } catch (err: any) {
+          lastError = err.message;
+          logger.log('warn', `MTA: MX ${mx.exchange} failed for ${domain}: ${err.message}`);
         }
       }
 
+      if (!delivered) {
+        results.push({ domain, success: false, error: lastError });
+        logger.log('error', `MTA: all MX hosts failed for ${domain}`);
+      }
+    }
+
+    const allFailed = results.every(r => !r.success);
+    if (allFailed) {
+      const summary = results.map(r => `${r.domain}: ${r.error}`).join('; ');
+      throw new Error(`MTA delivery failed for all domains: ${summary}`);
+    }
+
+    return {
+      recipients: allRecipients.length,
+      domainResults: results,
+    };
+  }
+  
   /**
    * Default handler for process mode delivery
    * @param item Queue item
@@ -584,16 +666,10 @@ export class MultiModeDeliverySystem extends EventEmitter {
         await this.applyDkimSigning(email, item.route.action.options?.mtaOptions || {});
       }
       
-      logger.log('info', `Email successfully processed in store-and-forward mode`);
+      logger.log('info', `Email successfully processed in store-and-forward mode, delivering via MTA`);
 
-      // Simulate successful delivery
-      return {
-        recipients: email.getAllRecipients().length,
-        subject: email.subject,
-        scanned: !!route?.action.options?.contentScanning,
-        transformed: !!(route?.action.options?.transformations && route?.action.options?.transformations.length > 0),
-        dkimSigned: !!(item.route?.action.options?.mtaOptions?.dkimSign || item.route?.action.process?.dkim)
-      };
+      // After scanning + transformations, deliver via MTA
+      return await this.handleMtaDelivery(item);
     } catch (error: any) {
       logger.log('error', `Failed to process email: ${error.message}`);
       throw error;

ts/mail/routing/classes.dkim.manager.ts

@@ -0,0 +1,157 @@
+import { logger } from '../../logger.js';
+import { DKIMCreator } from '../security/classes.dkimcreator.js';
+import { DomainRegistry } from './classes.domain.registry.js';
+import { RustSecurityBridge } from '../../security/classes.rustsecuritybridge.js';
+import { Email } from '../core/classes.email.js';
+
+/** External DcRouter interface shape used by DkimManager */
+interface DcRouter {
+  storageManager: any;
+  dnsServer?: any;
+}
+
+/**
+ * Manages DKIM key setup, rotation, and signing for all configured domains
+ */
+export class DkimManager {
+  private dkimKeys: Map<string, string> = new Map();
+
+  constructor(
+    private dkimCreator: DKIMCreator,
+    private domainRegistry: DomainRegistry,
+    private dcRouter: DcRouter,
+    private rustBridge: RustSecurityBridge,
+  ) {}
+
+  async setupDkimForDomains(): Promise<void> {
+    const domainConfigs = this.domainRegistry.getAllConfigs();
+
+    if (domainConfigs.length === 0) {
+      logger.log('warn', 'No domains configured for DKIM');
+      return;
+    }
+
+    for (const domainConfig of domainConfigs) {
+      const domain = domainConfig.domain;
+      const selector = domainConfig.dkim?.selector || 'default';
+
+      try {
+        let keyPair: { privateKey: string; publicKey: string };
+
+        try {
+          keyPair = await this.dkimCreator.readDKIMKeys(domain);
+          logger.log('info', `Using existing DKIM keys for domain: ${domain}`);
+        } catch (error) {
+          keyPair = await this.dkimCreator.createDKIMKeys();
+          await this.dkimCreator.createAndStoreDKIMKeys(domain);
+          logger.log('info', `Generated new DKIM keys for domain: ${domain}`);
+        }
+
+        this.dkimKeys.set(domain, keyPair.privateKey);
+        logger.log('info', `DKIM keys loaded for domain: ${domain} with selector: ${selector}`);
+      } catch (error) {
+        logger.log('error', `Failed to set up DKIM for domain ${domain}: ${error.message}`);
+      }
+    }
+  }
+
+  async checkAndRotateDkimKeys(): Promise<void> {
+    const domainConfigs = this.domainRegistry.getAllConfigs();
+
+    for (const domainConfig of domainConfigs) {
+      const domain = domainConfig.domain;
+      const selector = domainConfig.dkim?.selector || 'default';
+      const rotateKeys = domainConfig.dkim?.rotateKeys || false;
+      const rotationInterval = domainConfig.dkim?.rotationInterval || 90;
+      const keySize = domainConfig.dkim?.keySize || 2048;
+
+      if (!rotateKeys) {
+        logger.log('debug', `DKIM key rotation disabled for ${domain}`);
+        continue;
+      }
+
+      try {
+        const needsRotation = await this.dkimCreator.needsRotation(domain, selector, rotationInterval);
+
+        if (needsRotation) {
+          logger.log('info', `DKIM keys need rotation for ${domain} (selector: ${selector})`);
+
+          const newSelector = await this.dkimCreator.rotateDkimKeys(domain, selector, keySize);
+
+          domainConfig.dkim = {
+            ...domainConfig.dkim,
+            selector: newSelector
+          };
+
+          if (domainConfig.dnsMode === 'internal-dns' && this.dcRouter.dnsServer) {
+            const keyPair = await this.dkimCreator.readDKIMKeysForSelector(domain, newSelector);
+            const publicKeyBase64 = keyPair.publicKey
+              .replace(/-----BEGIN PUBLIC KEY-----/g, '')
+              .replace(/-----END PUBLIC KEY-----/g, '')
+              .replace(/\s/g, '');
+
+            const ttl = domainConfig.dns?.internal?.ttl || 3600;
+
+            this.dcRouter.dnsServer.registerHandler(
+              `${newSelector}._domainkey.${domain}`,
+              ['TXT'],
+              () => ({
+                name: `${newSelector}._domainkey.${domain}`,
+                type: 'TXT',
+                class: 'IN',
+                ttl: ttl,
+                data: `v=DKIM1; k=rsa; p=${publicKeyBase64}`
+              })
+            );
+
+            logger.log('info', `DKIM DNS handler registered for new selector: ${newSelector}._domainkey.${domain}`);
+
+            await this.dcRouter.storageManager.set(
+              `/email/dkim/${domain}/public.key`,
+              keyPair.publicKey
+            );
+          }
+
+          this.dkimCreator.cleanupOldKeys(domain, 30).catch(error => {
+            logger.log('warn', `Failed to cleanup old DKIM keys for ${domain}: ${error.message}`);
+          });
+
+        } else {
+          logger.log('debug', `DKIM keys for ${domain} are up to date`);
+        }
+      } catch (error) {
+        logger.log('error', `Failed to check/rotate DKIM keys for ${domain}: ${error.message}`);
+      }
+    }
+  }
+
+  async handleDkimSigning(email: Email, domain: string, selector: string): Promise<void> {
+    try {
+      await this.dkimCreator.handleDKIMKeysForDomain(domain);
+      const { privateKey } = await this.dkimCreator.readDKIMKeys(domain);
+      const rawEmail = email.toRFC822String();
+
+      // Detect key type from PEM header
+      const keyType = privateKey.includes('ED25519') ? 'ed25519' : 'rsa';
+
+      const signResult = await this.rustBridge.signDkim({
+        rawMessage: rawEmail,
+        domain,
+        selector,
+        privateKey,
+        keyType,
+      });
+
+      if (signResult.header) {
+        email.addHeader('DKIM-Signature', signResult.header);
+        logger.log('info', `Successfully added DKIM signature for ${domain}`);
+      }
+    } catch (error) {
+      logger.log('error', `Failed to sign email with DKIM: ${error.message}`);
+    }
+  }
+
+  getDkimKey(domain: string): string | undefined {
+    return this.dkimKeys.get(domain);
+  }
+}

ts/mail/routing/classes.email.action.executor.ts

@@ -0,0 +1,175 @@
+import { logger } from '../../logger.js';
+import {
+  SecurityLogger,
+  SecurityLogLevel,
+  SecurityEventType
+} from '../../security/index.js';
+import type { IEmailAction, IEmailContext } from './interfaces.js';
+import { Email } from '../core/classes.email.js';
+import { BounceManager } from '../core/classes.bouncemanager.js';
+import { UnifiedDeliveryQueue } from '../delivery/classes.delivery.queue.js';
+import type { ISmtpSendResult } from '../../security/classes.rustsecuritybridge.js';
+
+/**
+ * Dependencies injected from UnifiedEmailServer to avoid circular imports
+ */
+export interface IActionExecutorDeps {
+  sendOutboundEmail: (host: string, port: number, email: Email, options?: {
+    auth?: { user: string; pass: string };
+    dkimDomain?: string;
+    dkimSelector?: string;
+    tlsOpportunistic?: boolean;
+  }) => Promise<ISmtpSendResult>;
+  bounceManager: BounceManager;
+  deliveryQueue: UnifiedDeliveryQueue;
+}
+
+/**
+ * Executes email routing actions (forward, process, deliver, reject)
+ */
+export class EmailActionExecutor {
+  constructor(private deps: IActionExecutorDeps) {}
+
+  async executeAction(action: IEmailAction, email: Email, context: IEmailContext): Promise<void> {
+    switch (action.type) {
+      case 'forward':
+        await this.handleForwardAction(action, email, context);
+        break;
+      case 'process':
+        await this.handleProcessAction(action, email, context);
+        break;
+      case 'deliver':
+        await this.handleDeliverAction(action, email, context);
+        break;
+      case 'reject':
+        await this.handleRejectAction(action, email, context);
+        break;
+      default:
+        throw new Error(`Unknown action type: ${(action as any).type}`);
+    }
+  }
+
+  private async handleForwardAction(action: IEmailAction, email: Email, context: IEmailContext): Promise<void> {
+    if (!action.forward) {
+      throw new Error('Forward action requires forward configuration');
+    }
+
+    const { host, port = 25, auth, addHeaders } = action.forward;
+
+    logger.log('info', `Forwarding email to ${host}:${port}`);
+
+    // Add forwarding headers
+    if (addHeaders) {
+      for (const [key, value] of Object.entries(addHeaders)) {
+        email.headers[key] = value;
+      }
+    }
+
+    // Add standard forwarding headers
+    email.headers['X-Forwarded-For'] = context.session.remoteAddress || 'unknown';
+    email.headers['X-Forwarded-To'] = email.to.join(', ');
+    email.headers['X-Forwarded-Date'] = new Date().toISOString();
+
+    try {
+      // Send email via Rust SMTP client
+      await this.deps.sendOutboundEmail(host, port, email, {
+        auth: auth as { user: string; pass: string } | undefined,
+      });
+
+      logger.log('info', `Successfully forwarded email to ${host}:${port}`);
+
+      SecurityLogger.getInstance().logEvent({
+        level: SecurityLogLevel.INFO,
+        type: SecurityEventType.EMAIL_FORWARDING,
+        message: 'Email forwarded successfully',
+        ipAddress: context.session.remoteAddress,
+        details: {
+          sessionId: context.session.id,
+          routeName: context.session.matchedRoute?.name,
+          targetHost: host,
+          targetPort: port,
+          recipients: email.to
+        },
+        success: true
+      });
+    } catch (error) {
+      logger.log('error', `Failed to forward email: ${error.message}`);
+
+      SecurityLogger.getInstance().logEvent({
+        level: SecurityLogLevel.ERROR,
+        type: SecurityEventType.EMAIL_FORWARDING,
+        message: 'Email forwarding failed',
+        ipAddress: context.session.remoteAddress,
+        details: {
+          sessionId: context.session.id,
+          routeName: context.session.matchedRoute?.name,
+          targetHost: host,
+          targetPort: port,
+          error: error.message
+        },
+        success: false
+      });
+
+      // Handle as bounce
+      for (const recipient of email.getAllRecipients()) {
+        await this.deps.bounceManager.processSmtpFailure(recipient, error.message, {
+          sender: email.from,
+          originalEmailId: email.headers['Message-ID'] as string
+        });
+      }
+      throw error;
+    }
+  }
+
+  private async handleProcessAction(action: IEmailAction, email: Email, context: IEmailContext): Promise<void> {
+    logger.log('info', `Processing email with action options`);
+
+    // Apply scanning if requested
+    if (action.process?.scan) {
+      logger.log('info', 'Content scanning requested');
+    }
+
+    // Queue for delivery
+    const queue = action.process?.queue || 'normal';
+    await this.deps.deliveryQueue.enqueue(email, 'process', context.session.matchedRoute!);
+
+    logger.log('info', `Email queued for delivery in ${queue} queue`);
+  }
+
+  private async handleDeliverAction(_action: IEmailAction, email: Email, context: IEmailContext): Promise<void> {
+    logger.log('info', `Delivering email locally`);
+
+    // Queue for local delivery
+    await this.deps.deliveryQueue.enqueue(email, 'mta', context.session.matchedRoute!);
+
+    logger.log('info', 'Email queued for local delivery');
+  }
+
+  private async handleRejectAction(action: IEmailAction, _email: Email, context: IEmailContext): Promise<void> {
+    const code = action.reject?.code || 550;
+    const message = action.reject?.message || 'Message rejected';
+
+    logger.log('info', `Rejecting email with code ${code}: ${message}`);
+
+    SecurityLogger.getInstance().logEvent({
+      level: SecurityLogLevel.WARN,
+      type: SecurityEventType.EMAIL_PROCESSING,
+      message: 'Email rejected by routing rule',
+      ipAddress: context.session.remoteAddress,
+      details: {
+        sessionId: context.session.id,
+        routeName: context.session.matchedRoute?.name,
+        rejectCode: code,
+        rejectMessage: message,
+        from: _email.from,
+        to: _email.to
+      },
+      success: false
+    });
+
+    // Throw error with SMTP code and message
+    const error = new Error(message);
+    (error as any).responseCode = code;
+    throw error;
+  }
+}

ts/mail/routing/classes.email.config.ts

@@ -1,82 +0,0 @@
-import type { EmailProcessingMode } from '../delivery/interfaces.js';
-
-// Re-export EmailProcessingMode type
-export type { EmailProcessingMode };
-
-
-/**
- * Domain rule interface for pattern-based routing
- */
-export interface IDomainRule {
-  // Domain pattern (e.g., "*@example.com", "*@*.example.net")
-  pattern: string;
-  
-  // Handling mode for this pattern
-  mode: EmailProcessingMode;
-  
-  // Forward mode configuration
-  target?: {
-    server: string;
-    port?: number;
-    useTls?: boolean;
-    authentication?: {
-      user?: string;
-      pass?: string;
-    };
-  };
-  
-  // MTA mode configuration
-  mtaOptions?: IMtaOptions;
-  
-  // Process mode configuration
-  contentScanning?: boolean;
-  scanners?: IContentScanner[];
-  transformations?: ITransformation[];
-  
-  // Rate limits for this domain
-  rateLimits?: {
-    maxMessagesPerMinute?: number;
-    maxRecipientsPerMessage?: number;
-  };
-}
-
-/**
- * MTA options interface
- */
-export interface IMtaOptions {
-  domain?: string;
-  allowLocalDelivery?: boolean;
-  localDeliveryPath?: string;
-  dkimSign?: boolean;
-  dkimOptions?: {
-    domainName: string;
-    keySelector: string;
-    privateKey?: string;
-  };
-  smtpBanner?: string;
-  maxConnections?: number;
-  connTimeout?: number;
-  spoolDir?: string;
-}
-
-/**
- * Content scanner interface
- */
-export interface IContentScanner {
-  type: 'spam' | 'virus' | 'attachment';
-  threshold?: number;
-  action: 'tag' | 'reject';
-  blockedExtensions?: string[];
-}
-
-/**
- * Transformation interface
- */
-export interface ITransformation {
-  type: string;
-  header?: string;
-  value?: string;
-  domains?: string[];
-  append?: boolean;
-  [key: string]: any;
-}

ts/mail/routing/classes.unified.email.server.ts

@@ -8,7 +8,6 @@ import {
   SecurityEventType
 } from '../../security/index.js';
 import { DKIMCreator } from '../security/classes.dkimcreator.js';
-import { IPReputationChecker } from '../../security/classes.ipreputationchecker.js';
 import { RustSecurityBridge } from '../../security/classes.rustsecuritybridge.js';
 import type { IEmailReceivedEvent, IAuthRequestEvent, IEmailData } from '../../security/classes.rustsecuritybridge.js';
 import { EmailRouter } from './classes.email.router.js';
@@ -23,6 +22,10 @@ import { UnifiedDeliveryQueue, type IQueueOptions } from '../delivery/classes.de
 import { UnifiedRateLimiter, type IHierarchicalRateLimits } from '../delivery/classes.unified.rate.limiter.js';
 import { SmtpState } from '../delivery/interfaces.js';
 import type { EmailProcessingMode, ISmtpSession as IBaseSmtpSession } from '../delivery/interfaces.js';
+import { EmailActionExecutor } from './classes.email.action.executor.js';
+import { DkimManager } from './classes.dkim.manager.js';
+
+
 /** External DcRouter interface shape used by UnifiedEmailServer */
 interface DcRouter {
   storageManager: any;
@@ -160,12 +163,14 @@ export class UnifiedEmailServer extends EventEmitter {
   // Add components needed for sending and securing emails
   public dkimCreator: DKIMCreator;
   private rustBridge: RustSecurityBridge;
-  private ipReputationChecker: IPReputationChecker;
   private bounceManager: BounceManager;
   public deliveryQueue: UnifiedDeliveryQueue;
   public deliverySystem: MultiModeDeliverySystem;
   private rateLimiter: UnifiedRateLimiter; // TODO: Implement rate limiting in SMTP server handlers
-  private dkimKeys: Map<string, string> = new Map(); // domain -> private key
+
+  // Extracted subsystems
+  private actionExecutor: EmailActionExecutor;
+  private dkimManager: DkimManager;
 
   constructor(dcRouter: DcRouter, options: IUnifiedEmailServerOptions) {
     super();
@@ -188,13 +193,6 @@ export class UnifiedEmailServer extends EventEmitter {
     // Initialize DKIM creator with storage manager
     this.dkimCreator = new DKIMCreator(paths.keysDir, dcRouter.storageManager);
 
-    // Initialize IP reputation checker with storage manager
-    this.ipReputationChecker = IPReputationChecker.getInstance({
-      enableLocalCache: true,
-      enableDNSBL: true,
-      enableIPInfo: true
-    }, dcRouter.storageManager);
-    
     // Initialize bounce manager with storage manager
     this.bounceManager = new BounceManager({
       maxCacheSize: 10000,
@@ -247,6 +245,16 @@ export class UnifiedEmailServer extends EventEmitter {
 
     this.deliverySystem = new MultiModeDeliverySystem(this.deliveryQueue, deliveryOptions, this);
 
+    // Initialize action executor
+    this.actionExecutor = new EmailActionExecutor({
+      sendOutboundEmail: this.sendOutboundEmail.bind(this),
+      bounceManager: this.bounceManager,
+      deliveryQueue: this.deliveryQueue,
+    });
+
+    // Initialize DKIM manager
+    this.dkimManager = new DkimManager(this.dkimCreator, this.domainRegistry, dcRouter, this.rustBridge);
+
     // Initialize statistics
     this.stats = {
       startTime: new Date(),
@@ -277,6 +285,7 @@ export class UnifiedEmailServer extends EventEmitter {
     auth?: { user: string; pass: string };
     dkimDomain?: string;
     dkimSelector?: string;
+    tlsOpportunistic?: boolean;
   }): Promise<ISmtpSendResult> {
     // Build DKIM config if domain has keys
     let dkim: { domain: string; selector: string; privateKey: string } | undefined;
@@ -313,6 +322,7 @@ export class UnifiedEmailServer extends EventEmitter {
       socketTimeoutSecs: Math.floor((this.options.outbound?.socketTimeout || 120000) / 1000),
       poolKey: `${host}:${port}`,
       maxPoolConnections: this.options.outbound?.maxConnections || 10,
+      tlsOpportunistic: options?.tlsOpportunistic ?? (port === 25),
     });
   }
 
@@ -323,70 +333,62 @@ export class UnifiedEmailServer extends EventEmitter {
     logger.log('info', `Starting UnifiedEmailServer on ports: ${(this.options.ports as number[]).join(', ')}`);
 
     try {
-      // Initialize the delivery queue
+      await this.startDeliveryPipeline();
+      await this.startRustBridge();
+      await this.initializeDkimAndDns();
+      this.registerBridgeEventHandlers();
+      await this.startSmtpServer();
+      logger.log('info', 'UnifiedEmailServer started successfully');
+      this.emit('started');
+    } catch (error) {
+      logger.log('error', `Failed to start UnifiedEmailServer: ${error.message}`);
+      throw error;
+    }
+  }
+
+  private async startDeliveryPipeline(): Promise<void> {
     await this.deliveryQueue.initialize();
     logger.log('info', 'Email delivery queue initialized');
 
-      // Start the delivery system
     await this.deliverySystem.start();
     logger.log('info', 'Email delivery system started');
+  }
 
-      // Start Rust security bridge — required for all security operations
+  private async startRustBridge(): Promise<void> {
     const bridgeOk = await this.rustBridge.start();
     if (!bridgeOk) {
       throw new Error('Rust security bridge failed to start. The mailer-bin binary is required. Run "pnpm build" to compile it.');
     }
     logger.log('info', 'Rust security bridge started — Rust is the primary security backend');
 
-      // Listen for bridge state changes to propagate resilience events
     this.rustBridge.on('stateChange', ({ oldState, newState }: { oldState: string; newState: string }) => {
       if (newState === 'failed') this.emit('bridgeFailed');
       else if (newState === 'restarting') this.emit('bridgeRestarting');
       else if (newState === 'running' && oldState === 'restarting') this.emit('bridgeRecovered');
     });
+  }
 
-      // Set up DKIM for all domains
-      await this.setupDkimForDomains();
+  private async initializeDkimAndDns(): Promise<void> {
+    await this.dkimManager.setupDkimForDomains();
     logger.log('info', 'DKIM configuration completed for all domains');
 
-      // Create DNS manager and ensure all DNS records are created
     const dnsManager = new DnsManager(this.dcRouter);
     await dnsManager.ensureDnsRecords(this.domainRegistry.getAllConfigs(), this.dkimCreator);
     logger.log('info', 'DNS records ensured for all configured domains');
 
-      // Apply per-domain rate limits
     this.applyDomainRateLimits();
     logger.log('info', 'Per-domain rate limits configured');
 
-      // Check and rotate DKIM keys if needed
-      await this.checkAndRotateDkimKeys();
+    await this.dkimManager.checkAndRotateDkimKeys();
     logger.log('info', 'DKIM key rotation check completed');
-      
-      // Ensure we have the necessary TLS options
-      const hasTlsConfig = this.options.tls?.keyPath && this.options.tls?.certPath;
-
-      // Prepare the certificate and key if available
-      let tlsCertPem: string | undefined;
-      let tlsKeyPem: string | undefined;
-
-      if (hasTlsConfig) {
-        try {
-          tlsKeyPem = plugins.fs.readFileSync(this.options.tls.keyPath!, 'utf8');
-          tlsCertPem = plugins.fs.readFileSync(this.options.tls.certPath!, 'utf8');
-          logger.log('info', 'TLS certificates loaded successfully');
-        } catch (error) {
-          logger.log('warn', `Failed to load TLS certificates: ${error.message}`);
-        }
   }
 
-      // --- Start Rust SMTP server ---
-      // Register event handlers for email reception and auth
+  private registerBridgeEventHandlers(): void {
     this.rustBridge.onEmailReceived(async (data) => {
       try {
         await this.handleRustEmailReceived(data);
       } catch (err) {
         logger.log('error', `Error handling email from Rust SMTP: ${(err as Error).message}`);
-          // Send rejection back to Rust (may fail if bridge is restarting)
         try {
           await this.rustBridge.sendEmailProcessingResult({
             correlationId: data.correlationId,
@@ -417,7 +419,38 @@ export class UnifiedEmailServer extends EventEmitter {
       }
     });
 
-      // Determine which ports need STARTTLS and which need implicit TLS
+    this.rustBridge.onScramCredentialRequest(async (data) => {
+      try {
+        await this.handleScramCredentialRequest(data);
+      } catch (err) {
+        logger.log('error', `Error handling SCRAM credential request: ${(err as Error).message}`);
+        try {
+          await this.rustBridge.sendScramCredentialResult({
+            correlationId: data.correlationId,
+            found: false,
+          });
+        } catch (sendErr) {
+          logger.log('warn', `Could not send SCRAM credential rejection: ${(sendErr as Error).message}`);
+        }
+      }
+    });
+  }
+
+  private async startSmtpServer(): Promise<void> {
+    const hasTlsConfig = this.options.tls?.keyPath && this.options.tls?.certPath;
+    let tlsCertPem: string | undefined;
+    let tlsKeyPem: string | undefined;
+
+    if (hasTlsConfig) {
+      try {
+        tlsKeyPem = plugins.fs.readFileSync(this.options.tls.keyPath!, 'utf8');
+        tlsCertPem = plugins.fs.readFileSync(this.options.tls.certPath!, 'utf8');
+        logger.log('info', 'TLS certificates loaded successfully');
+      } catch (error) {
+        logger.log('warn', `Failed to load TLS certificates: ${error.message}`);
+      }
+    }
+
     const smtpPorts = (this.options.ports as number[]).filter(p => p !== 465);
     const securePort = (this.options.ports as number[]).find(p => p === 465);
 
@@ -449,12 +482,6 @@ export class UnifiedEmailServer extends EventEmitter {
     }
 
     logger.log('info', `Rust SMTP server listening on ports: ${smtpPorts.join(', ')}${securePort ? ` + ${securePort} (TLS)` : ''}`);
-      logger.log('info', 'UnifiedEmailServer started successfully');
-      this.emit('started');
-    } catch (error) {
-      logger.log('error', `Failed to start UnifiedEmailServer: ${error.message}`);
-      throw error;
-    }
   }
 
   /**
@@ -512,8 +539,6 @@ export class UnifiedEmailServer extends EventEmitter {
 
   /**
    * Handle an emailReceived event from the Rust SMTP server.
-   * Decodes the email data, processes it through the routing system,
-   * and sends back the result via the correlation-ID callback.
    */
   private async handleRustEmailReceived(data: IEmailReceivedEvent): Promise<void> {
     const { correlationId, mailFrom, rcptTo, remoteAddr, clientHostname, secure, authenticatedUser } = data;
@@ -588,7 +613,6 @@ export class UnifiedEmailServer extends EventEmitter {
 
   /**
    * Handle an authRequest event from the Rust SMTP server.
-   * Validates credentials and sends back the result.
    */
   private async handleRustAuthRequest(data: IAuthRequestEvent): Promise<void> {
     const { correlationId, username, password, remoteAddr } = data;
@@ -616,6 +640,53 @@ export class UnifiedEmailServer extends EventEmitter {
     }
   }
 
+  /**
+   * Handle a SCRAM credential request from the Rust SMTP server.
+   * Computes SCRAM-SHA-256 credentials from the stored password for the given user.
+   */
+  private async handleScramCredentialRequest(data: { correlationId: string; username: string; remoteAddr: string }): Promise<void> {
+    const { correlationId, username, remoteAddr } = data;
+    const crypto = await import('crypto');
+
+    logger.log('info', `SCRAM credential request for user=${username} from=${remoteAddr}`);
+
+    const users = this.options.auth?.users || [];
+    const matched = users.find(u => u.username === username);
+
+    if (!matched) {
+      await this.rustBridge.sendScramCredentialResult({
+        correlationId,
+        found: false,
+      });
+      return;
+    }
+
+    // Compute SCRAM-SHA-256 credentials from plaintext password
+    const salt = crypto.randomBytes(16);
+    const iterations = 4096;
+
+    // SaltedPassword = PBKDF2-HMAC-SHA256(password, salt, iterations, 32)
+    const saltedPassword = crypto.pbkdf2Sync(matched.password, salt, iterations, 32, 'sha256');
+
+    // ClientKey = HMAC-SHA256(SaltedPassword, "Client Key")
+    const clientKey = crypto.createHmac('sha256', saltedPassword).update('Client Key').digest();
+
+    // StoredKey = SHA256(ClientKey)
+    const storedKey = crypto.createHash('sha256').update(clientKey).digest();
+
+    // ServerKey = HMAC-SHA256(SaltedPassword, "Server Key")
+    const serverKey = crypto.createHmac('sha256', saltedPassword).update('Server Key').digest();
+
+    await this.rustBridge.sendScramCredentialResult({
+      correlationId,
+      found: true,
+      salt: salt.toString('base64'),
+      iterations,
+      storedKey: storedKey.toString('base64'),
+      serverKey: serverKey.toString('base64'),
+    });
+  }
+
   /**
    * Verify inbound email security (DKIM/SPF/DMARC) using pre-computed Rust results
    * or falling back to IPC call if no pre-computed results are available.
@@ -740,14 +811,12 @@ export class UnifiedEmailServer extends EventEmitter {
     }
 
     // First check if this is a bounce notification email
-    // Look for common bounce notification subject patterns
     const subject = email.subject || '';
     const isBounceLike = /mail delivery|delivery (failed|status|notification)|failure notice|returned mail|undeliverable|delivery problem/i.test(subject);
 
     if (isBounceLike) {
       logger.log('info', `Email subject matches bounce notification pattern: "${subject}"`);
 
-      // Try to process as a bounce
       const isBounce = await this.processBounceNotification(email);
 
       if (isBounce) {
@@ -763,7 +832,6 @@ export class UnifiedEmailServer extends EventEmitter {
     const route = await this.emailRouter.evaluateRoutes(context);
 
     if (!route) {
-      // No matching route - reject
       throw new Error('No matching route for email');
     }
 
@@ -771,221 +839,12 @@ export class UnifiedEmailServer extends EventEmitter {
     session.matchedRoute = route;
 
     // Execute action based on route
-    await this.executeAction(route.action, email, context);
+    await this.actionExecutor.executeAction(route.action, email, context);
 
     // Return the processed email
     return email;
   }
 
-  /**
-   * Execute action based on route configuration
-   */
-  private async executeAction(action: IEmailAction, email: Email, context: IEmailContext): Promise<void> {
-    switch (action.type) {
-      case 'forward':
-        await this.handleForwardAction(action, email, context);
-        break;
-        
-      case 'process':
-        await this.handleProcessAction(action, email, context);
-        break;
-        
-      case 'deliver':
-        await this.handleDeliverAction(action, email, context);
-        break;
-        
-      case 'reject':
-        await this.handleRejectAction(action, email, context);
-        break;
-        
-      default:
-        throw new Error(`Unknown action type: ${(action as any).type}`);
-    }
-  }
-  
-  /**
-   * Handle forward action
-   */
-  private async handleForwardAction(_action: IEmailAction, email: Email, context: IEmailContext): Promise<void> {
-    if (!_action.forward) {
-      throw new Error('Forward action requires forward configuration');
-    }
-    
-    const { host, port = 25, auth, addHeaders } = _action.forward;
-    
-    logger.log('info', `Forwarding email to ${host}:${port}`);
-    
-    // Add forwarding headers
-    if (addHeaders) {
-      for (const [key, value] of Object.entries(addHeaders)) {
-        email.headers[key] = value;
-      }
-    }
-    
-    // Add standard forwarding headers
-    email.headers['X-Forwarded-For'] = context.session.remoteAddress || 'unknown';
-    email.headers['X-Forwarded-To'] = email.to.join(', ');
-    email.headers['X-Forwarded-Date'] = new Date().toISOString();
-    
-    try {
-      // Send email via Rust SMTP client
-      await this.sendOutboundEmail(host, port, email, {
-        auth: auth as { user: string; pass: string } | undefined,
-      });
-
-      logger.log('info', `Successfully forwarded email to ${host}:${port}`);
-      
-      SecurityLogger.getInstance().logEvent({
-        level: SecurityLogLevel.INFO,
-        type: SecurityEventType.EMAIL_FORWARDING,
-        message: 'Email forwarded successfully',
-        ipAddress: context.session.remoteAddress,
-        details: {
-          sessionId: context.session.id,
-          routeName: context.session.matchedRoute?.name,
-          targetHost: host,
-          targetPort: port,
-          recipients: email.to
-        },
-        success: true
-      });
-    } catch (error) {
-      logger.log('error', `Failed to forward email: ${error.message}`);
-      
-      SecurityLogger.getInstance().logEvent({
-        level: SecurityLogLevel.ERROR,
-        type: SecurityEventType.EMAIL_FORWARDING,
-        message: 'Email forwarding failed',
-        ipAddress: context.session.remoteAddress,
-        details: {
-          sessionId: context.session.id,
-          routeName: context.session.matchedRoute?.name,
-          targetHost: host,
-          targetPort: port,
-          error: error.message
-        },
-        success: false
-      });
-      
-      // Handle as bounce
-      for (const recipient of email.getAllRecipients()) {
-        await this.bounceManager.processSmtpFailure(recipient, error.message, {
-          sender: email.from,
-          originalEmailId: email.headers['Message-ID'] as string
-        });
-      }
-      throw error;
-    }
-  }
-  
-  /**
-   * Handle process action
-   */
-  private async handleProcessAction(action: IEmailAction, email: Email, context: IEmailContext): Promise<void> {
-    logger.log('info', `Processing email with action options`);
-    
-    // Apply scanning if requested
-    if (action.process?.scan) {
-      // Use existing content scanner
-      // Note: ContentScanner integration would go here
-      logger.log('info', 'Content scanning requested');
-    }
-    
-    // Note: DKIM signing will be applied at delivery time to ensure signature validity
-    
-    // Queue for delivery
-    const queue = action.process?.queue || 'normal';
-    await this.deliveryQueue.enqueue(email, 'process', context.session.matchedRoute!);
-    
-    logger.log('info', `Email queued for delivery in ${queue} queue`);
-  }
-  
-  /**
-   * Handle deliver action
-   */
-  private async handleDeliverAction(_action: IEmailAction, email: Email, context: IEmailContext): Promise<void> {
-    logger.log('info', `Delivering email locally`);
-    
-    // Queue for local delivery
-    await this.deliveryQueue.enqueue(email, 'mta', context.session.matchedRoute!);
-    
-    logger.log('info', 'Email queued for local delivery');
-  }
-  
-  /**
-   * Handle reject action
-   */
-  private async handleRejectAction(action: IEmailAction, email: Email, context: IEmailContext): Promise<void> {
-    const code = action.reject?.code || 550;
-    const message = action.reject?.message || 'Message rejected';
-    
-    logger.log('info', `Rejecting email with code ${code}: ${message}`);
-    
-    SecurityLogger.getInstance().logEvent({
-      level: SecurityLogLevel.WARN,
-      type: SecurityEventType.EMAIL_PROCESSING,
-      message: 'Email rejected by routing rule',
-      ipAddress: context.session.remoteAddress,
-      details: {
-        sessionId: context.session.id,
-        routeName: context.session.matchedRoute?.name,
-        rejectCode: code,
-        rejectMessage: message,
-        from: email.from,
-        to: email.to
-      },
-      success: false
-    });
-    
-    // Throw error with SMTP code and message
-    const error = new Error(message);
-    (error as any).responseCode = code;
-    throw error;
-  }
-  
-  /**
-   * Set up DKIM configuration for all domains
-   */
-  private async setupDkimForDomains(): Promise<void> {
-    const domainConfigs = this.domainRegistry.getAllConfigs();
-    
-    if (domainConfigs.length === 0) {
-      logger.log('warn', 'No domains configured for DKIM');
-      return;
-    }
-    
-    for (const domainConfig of domainConfigs) {
-      const domain = domainConfig.domain;
-      const selector = domainConfig.dkim?.selector || 'default';
-      
-      try {
-        // Check if DKIM keys already exist for this domain
-        let keyPair: { privateKey: string; publicKey: string };
-        
-        try {
-          // Try to read existing keys
-          keyPair = await this.dkimCreator.readDKIMKeys(domain);
-          logger.log('info', `Using existing DKIM keys for domain: ${domain}`);
-        } catch (error) {
-          // Generate new keys if they don't exist
-          keyPair = await this.dkimCreator.createDKIMKeys();
-          // Store them for future use
-          await this.dkimCreator.createAndStoreDKIMKeys(domain);
-          logger.log('info', `Generated new DKIM keys for domain: ${domain}`);
-        }
-        
-        // Store the private key for signing
-        this.dkimKeys.set(domain, keyPair.privateKey);
-        
-        // DNS record creation is now handled by DnsManager
-        logger.log('info', `DKIM keys loaded for domain: ${domain} with selector: ${selector}`);
-      } catch (error) {
-        logger.log('error', `Failed to set up DKIM for domain ${domain}: ${error.message}`);
-      }
-    }
-  }
-  
-  
   /**
    * Apply per-domain rate limits from domain configurations
    */
@@ -997,12 +856,10 @@ export class UnifiedEmailServer extends EventEmitter {
         const domain = domainConfig.domain;
         const rateLimitConfig: any = {};
 
-        // Convert domain-specific rate limits to the format expected by UnifiedRateLimiter
         if (domainConfig.rateLimits.outbound) {
           if (domainConfig.rateLimits.outbound.messagesPerMinute) {
             rateLimitConfig.maxMessagesPerMinute = domainConfig.rateLimits.outbound.messagesPerMinute;
           }
-          // Note: messagesPerHour and messagesPerDay would need additional implementation in rate limiter
         }
 
         if (domainConfig.rateLimits.inbound) {
@@ -1017,7 +874,6 @@ export class UnifiedEmailServer extends EventEmitter {
           }
         }
 
-        // Apply the rate limits if we have any
         if (Object.keys(rateLimitConfig).length > 0) {
           this.rateLimiter.applyDomainLimits(domain, rateLimitConfig);
           logger.log('info', `Applied rate limits for domain ${domain}:`, rateLimitConfig);
@@ -1026,88 +882,6 @@ export class UnifiedEmailServer extends EventEmitter {
     }
   }
 
-  /**
-   * Check and rotate DKIM keys if needed
-   */
-  private async checkAndRotateDkimKeys(): Promise<void> {
-    const domainConfigs = this.domainRegistry.getAllConfigs();
-    
-    for (const domainConfig of domainConfigs) {
-      const domain = domainConfig.domain;
-      const selector = domainConfig.dkim?.selector || 'default';
-      const rotateKeys = domainConfig.dkim?.rotateKeys || false;
-      const rotationInterval = domainConfig.dkim?.rotationInterval || 90;
-      const keySize = domainConfig.dkim?.keySize || 2048;
-      
-      if (!rotateKeys) {
-        logger.log('debug', `DKIM key rotation disabled for ${domain}`);
-        continue;
-      }
-      
-      try {
-        // Check if keys need rotation
-        const needsRotation = await this.dkimCreator.needsRotation(domain, selector, rotationInterval);
-        
-        if (needsRotation) {
-          logger.log('info', `DKIM keys need rotation for ${domain} (selector: ${selector})`);
-          
-          // Rotate the keys
-          const newSelector = await this.dkimCreator.rotateDkimKeys(domain, selector, keySize);
-          
-          // Update the domain config with new selector
-          domainConfig.dkim = {
-            ...domainConfig.dkim,
-            selector: newSelector
-          };
-          
-          // Re-register DNS handler for new selector if internal-dns mode
-          if (domainConfig.dnsMode === 'internal-dns' && this.dcRouter.dnsServer) {
-            // Get new public key
-            const keyPair = await this.dkimCreator.readDKIMKeysForSelector(domain, newSelector);
-            const publicKeyBase64 = keyPair.publicKey
-              .replace(/-----BEGIN PUBLIC KEY-----/g, '')
-              .replace(/-----END PUBLIC KEY-----/g, '')
-              .replace(/\s/g, '');
-            
-            const ttl = domainConfig.dns?.internal?.ttl || 3600;
-            
-            // Register new selector
-            this.dcRouter.dnsServer.registerHandler(
-              `${newSelector}._domainkey.${domain}`,
-              ['TXT'],
-              () => ({
-                name: `${newSelector}._domainkey.${domain}`,
-                type: 'TXT',
-                class: 'IN',
-                ttl: ttl,
-                data: `v=DKIM1; k=rsa; p=${publicKeyBase64}`
-              })
-            );
-            
-            logger.log('info', `DKIM DNS handler registered for new selector: ${newSelector}._domainkey.${domain}`);
-            
-            // Store the updated public key in storage
-            await this.dcRouter.storageManager.set(
-              `/email/dkim/${domain}/public.key`,
-              keyPair.publicKey
-            );
-          }
-          
-          // Clean up old keys after grace period (async, don't wait)
-          this.dkimCreator.cleanupOldKeys(domain, 30).catch(error => {
-            logger.log('warn', `Failed to cleanup old DKIM keys for ${domain}: ${error.message}`);
-          });
-          
-        } else {
-          logger.log('debug', `DKIM keys for ${domain} are up to date`);
-        }
-      } catch (error) {
-        logger.log('error', `Failed to check/rotate DKIM keys for ${domain}: ${error.message}`);
-      }
-    }
-  }
-  
-  
   /**
    * Generate SmartProxy routes for email ports
    */
@@ -1121,26 +895,24 @@ export class UnifiedEmailServer extends EventEmitter {
 
     const actualPortMapping = portMapping || defaultPortMapping;
 
-    // Generate routes for each configured port
     for (const externalPort of this.options.ports) {
       const internalPort = actualPortMapping[externalPort] || externalPort + 10000;
 
       let routeName = 'email-route';
       let tlsMode = 'passthrough';
 
-      // Configure based on port
       switch (externalPort) {
         case 25:
           routeName = 'smtp-route';
-          tlsMode = 'passthrough'; // STARTTLS
+          tlsMode = 'passthrough';
           break;
         case 587:
           routeName = 'submission-route';
-          tlsMode = 'passthrough'; // STARTTLS
+          tlsMode = 'passthrough';
           break;
         case 465:
           routeName = 'smtps-route';
-          tlsMode = 'terminate'; // Implicit TLS
+          tlsMode = 'terminate';
           break;
         default:
           routeName = `email-port-${externalPort}-route`;
@@ -1171,7 +943,6 @@ export class UnifiedEmailServer extends EventEmitter {
    * Update server configuration
    */
   public updateOptions(options: Partial<IUnifiedEmailServerOptions>): void {
-    // Stop the server if changing ports
     const portsChanged = options.ports &&
       (!this.options.ports ||
        JSON.stringify(options.ports) !== JSON.stringify(this.options.ports));
@@ -1182,15 +953,12 @@ export class UnifiedEmailServer extends EventEmitter {
         this.start();
       });
     } else {
-      // Update options without restart
       this.options = { ...this.options, ...options };
 
-      // Update domain registry if domains changed
       if (options.domains) {
         this.domainRegistry = new DomainRegistry(options.domains, options.defaults || this.options.defaults);
       }
 
-      // Update email router if routes changed
       if (options.routes) {
         this.emailRouter.updateRoutes(options.routes);
       }
@@ -1219,21 +987,8 @@ export class UnifiedEmailServer extends EventEmitter {
     return this.domainRegistry;
   }
 
-  /**
-   * Update email routes dynamically
-   */
-  public updateRoutes(routes: IEmailRoute[]): void {
-    this.emailRouter.setRoutes(routes);
-    logger.log('info', `Updated email routes with ${routes.length} routes`);
-  }
-  
   /**
    * Send an email through the delivery system
-   * @param email The email to send
-   * @param mode The processing mode to use
-   * @param rule Optional rule to apply
-   * @param options Optional sending options
-   * @returns The ID of the queued email
    */
   public async sendEmail(
     email: Email,
@@ -1248,7 +1003,6 @@ export class UnifiedEmailServer extends EventEmitter {
     logger.log('info', `Sending email: ${email.subject} to ${email.to.join(', ')}`);
 
     try {
-      // Validate the email
       if (!email.from) {
         throw new Error('Email must have a sender address');
       }
@@ -1257,12 +1011,11 @@ export class UnifiedEmailServer extends EventEmitter {
         throw new Error('Email must have at least one recipient');
       }
 
-      // Check if any recipients are on the suppression list (unless explicitly skipped)
+      // Check if any recipients are on the suppression list
       if (!options?.skipSuppressionCheck) {
         const suppressedRecipients = email.to.filter(recipient => this.isEmailSuppressed(recipient));
 
         if (suppressedRecipients.length > 0) {
-          // Filter out suppressed recipients
           const originalCount = email.to.length;
           const suppressed = suppressedRecipients.map(recipient => {
             const info = this.getSuppressionInfo(recipient);
@@ -1275,26 +1028,21 @@ export class UnifiedEmailServer extends EventEmitter {
 
           logger.log('warn', `Filtering out ${suppressedRecipients.length} suppressed recipient(s)`, { suppressed });
 
-          // If all recipients are suppressed, throw an error
           if (suppressedRecipients.length === originalCount) {
             throw new Error('All recipients are on the suppression list');
           }
 
-          // Filter the recipients list to only include non-suppressed addresses
           email.to = email.to.filter(recipient => !this.isEmailSuppressed(recipient));
         }
       }
 
-      // Check if the sender domain has DKIM keys and sign the email if needed
+      // Sign with DKIM if configured
       if (mode === 'mta' && route?.action.options?.mtaOptions?.dkimSign) {
         const domain = email.from.split('@')[1];
-        await this.handleDkimSigning(email, domain, route.action.options.mtaOptions.dkimOptions?.keySelector || 'mta');
+        await this.dkimManager.handleDkimSigning(email, domain, route.action.options.mtaOptions.dkimOptions?.keySelector || 'mta');
       }
 
-      // Generate a unique ID for this email
       const id = plugins.uuid.v4();
-      
-      // Queue the email for delivery
       await this.deliveryQueue.enqueue(email, mode, route);
 
       logger.log('info', `Email queued with ID: ${id}`);
@@ -1305,51 +1053,14 @@ export class UnifiedEmailServer extends EventEmitter {
     }
   }
 
-  /**
-   * Handle DKIM signing for an email
-   * @param email The email to sign
-   * @param domain The domain to sign with
-   * @param selector The DKIM selector
-   */
-  private async handleDkimSigning(email: Email, domain: string, selector: string): Promise<void> {
-    try {
-      // Ensure we have DKIM keys for this domain
-      await this.dkimCreator.handleDKIMKeysForDomain(domain);
+  // -----------------------------------------------------------------------
+  // Bounce/suppression methods
+  // -----------------------------------------------------------------------
 
-      // Get the private key
-      const { privateKey } = await this.dkimCreator.readDKIMKeys(domain);
-
-      // Convert Email to raw format for signing
-      const rawEmail = email.toRFC822String();
-
-      // Sign the email via Rust bridge
-      const signResult = await this.rustBridge.signDkim({
-        rawMessage: rawEmail,
-        domain,
-        selector,
-        privateKey,
-      });
-
-      if (signResult.header) {
-        email.addHeader('DKIM-Signature', signResult.header);
-        logger.log('info', `Successfully added DKIM signature for ${domain}`);
-      }
-    } catch (error) {
-      logger.log('error', `Failed to sign email with DKIM: ${error.message}`);
-      // Continue without DKIM rather than failing the send
-    }
-  }
-  
-  /**
-   * Process a bounce notification email
-   * @param bounceEmail The email containing bounce notification information
-   * @returns Processed bounce record or null if not a bounce
-   */
   public async processBounceNotification(bounceEmail: Email): Promise<boolean> {
     logger.log('info', 'Processing potential bounce notification email');
 
     try {
-      // Process as a bounce notification (no conversion needed anymore)
       const bounceRecord = await this.bounceManager.processBounceEmail(bounceEmail);
 
       if (bounceRecord) {
@@ -1358,10 +1069,8 @@ export class UnifiedEmailServer extends EventEmitter {
           bounceCategory: bounceRecord.bounceCategory
         });
 
-        // Notify any registered listeners about the bounce
         this.emit('bounceProcessed', bounceRecord);
 
-        // Log security event
         SecurityLogger.getInstance().logEvent({
           level: SecurityLogLevel.INFO,
           type: SecurityEventType.EMAIL_VALIDATION,
@@ -1387,10 +1096,7 @@ export class UnifiedEmailServer extends EventEmitter {
         level: SecurityLogLevel.ERROR,
         type: SecurityEventType.EMAIL_VALIDATION,
         message: 'Failed to process bounce notification',
-        details: {
-          error: error.message,
-          subject: bounceEmail.subject
-        },
+        details: { error: error.message, subject: bounceEmail.subject },
         success: false
       });
 
@@ -1398,41 +1104,22 @@ export class UnifiedEmailServer extends EventEmitter {
     }
   }
 
-  /**
-   * Process an SMTP failure as a bounce
-   * @param recipient Recipient email that failed
-   * @param smtpResponse SMTP error response
-   * @param options Additional options for bounce processing
-   * @returns Processed bounce record
-   */
   public async processSmtpFailure(
     recipient: string,
     smtpResponse: string,
-    options: {
-      sender?: string;
-      originalEmailId?: string;
-      statusCode?: string;
-      headers?: Record<string, string>;
-    } = {}
+    options: { sender?: string; originalEmailId?: string; statusCode?: string; headers?: Record<string, string> } = {}
   ): Promise<boolean> {
     logger.log('info', `Processing SMTP failure for ${recipient}: ${smtpResponse}`);
 
     try {
-      // Process the SMTP failure through the bounce manager
-      const bounceRecord = await this.bounceManager.processSmtpFailure(
-        recipient,
-        smtpResponse,
-        options
-      );
+      const bounceRecord = await this.bounceManager.processSmtpFailure(recipient, smtpResponse, options);
 
       logger.log('info', `Successfully processed SMTP failure for ${recipient} as ${bounceRecord.bounceCategory} bounce`, {
         bounceType: bounceRecord.bounceType
       });
 
-      // Notify any registered listeners about the bounce
       this.emit('bounceProcessed', bounceRecord);
 
-      // Log security event
       SecurityLogger.getInstance().logEvent({
         level: SecurityLogLevel.INFO,
         type: SecurityEventType.EMAIL_VALIDATION,
@@ -1455,11 +1142,7 @@ export class UnifiedEmailServer extends EventEmitter {
         level: SecurityLogLevel.ERROR,
         type: SecurityEventType.EMAIL_VALIDATION,
         message: 'Failed to process SMTP failure',
-        details: {
-          recipient,
-          smtpResponse,
-          error: error.message
-        },
+        details: { recipient, smtpResponse, error: error.message },
         success: false
       });
 
@@ -1467,85 +1150,36 @@ export class UnifiedEmailServer extends EventEmitter {
     }
   }
 
-  /**
-   * Check if an email address is suppressed (has bounced previously)
-   * @param email Email address to check
-   * @returns Whether the email is suppressed
-   */
   public isEmailSuppressed(email: string): boolean {
     return this.bounceManager.isEmailSuppressed(email);
   }
 
-  /**
-   * Get suppression information for an email
-   * @param email Email address to check
-   * @returns Suppression information or null if not suppressed
-   */
-  public getSuppressionInfo(email: string): {
-    reason: string;
-    timestamp: number;
-    expiresAt?: number;
-  } | null {
+  public getSuppressionInfo(email: string): { reason: string; timestamp: number; expiresAt?: number } | null {
     return this.bounceManager.getSuppressionInfo(email);
   }
 
-  /**
-   * Get bounce history information for an email
-   * @param email Email address to check
-   * @returns Bounce history or null if no bounces
-   */
-  public getBounceHistory(email: string): {
-    lastBounce: number;
-    count: number;
-    type: BounceType;
-    category: BounceCategory;
-  } | null {
+  public getBounceHistory(email: string): { lastBounce: number; count: number; type: BounceType; category: BounceCategory } | null {
     return this.bounceManager.getBounceInfo(email);
   }
 
-  /**
-   * Get all suppressed email addresses
-   * @returns Array of suppressed email addresses
-   */
   public getSuppressionList(): string[] {
     return this.bounceManager.getSuppressionList();
   }
 
-  /**
-   * Get all hard bounced email addresses
-   * @returns Array of hard bounced email addresses
-   */
   public getHardBouncedAddresses(): string[] {
     return this.bounceManager.getHardBouncedAddresses();
   }
 
-  /**
-   * Add an email to the suppression list
-   * @param email Email address to suppress
-   * @param reason Reason for suppression
-   * @param expiresAt Optional expiration time (undefined for permanent)
-   */
   public addToSuppressionList(email: string, reason: string, expiresAt?: number): void {
     this.bounceManager.addToSuppressionList(email, reason, expiresAt);
     logger.log('info', `Added ${email} to suppression list: ${reason}`);
   }
 
-  /**
-   * Remove an email from the suppression list
-   * @param email Email address to remove from suppression
-   */
   public removeFromSuppressionList(email: string): void {
     this.bounceManager.removeFromSuppressionList(email);
     logger.log('info', `Removed ${email} from suppression list`);
   }
 
-  /**
-   * Record email bounce
-   * @param domain Sending domain
-   * @param receivingDomain Receiving domain that bounced
-   * @param bounceType Type of bounce (hard/soft)
-   * @param reason Bounce reason
-   */
   public recordBounce(domain: string, receivingDomain: string, bounceType: 'hard' | 'soft', reason: string): void {
     const bounceRecord = {
       id: `bounce_${Date.now()}_${Math.random().toString(36).substring(2, 9)}`,
@@ -1566,7 +1200,6 @@ export class UnifiedEmailServer extends EventEmitter {
 
   /**
    * Get the rate limiter instance
-   * @returns The unified rate limiter
    */
   public getRateLimiter(): UnifiedRateLimiter {
     return this.rateLimiter;

ts/mail/routing/index.ts

@@ -4,3 +4,6 @@ export * from './classes.unified.email.server.js';
 export * from './classes.dns.manager.js';
 export * from './interfaces.js';
 export * from './classes.domain.registry.js';
+export * from './classes.email.action.executor.js';
+export * from './classes.dkim.manager.js';
+

ts/mail/security/classes.dkimcreator.ts

@@ -115,7 +115,7 @@ export class DKIMCreator {
     }
   }
 
-  // Create a DKIM key pair - changed to public for API access
+  // Create an RSA DKIM key pair - changed to public for API access
   public async createDKIMKeys(): Promise<{ privateKey: string; publicKey: string }> {
     const { privateKey, publicKey } = await generateKeyPair('rsa', {
       modulusLength: 2048,
@@ -126,6 +126,16 @@ export class DKIMCreator {
     return { privateKey, publicKey };
   }
 
+  // Create an Ed25519 DKIM key pair (RFC 8463)
+  public async createEd25519Keys(): Promise<{ privateKey: string; publicKey: string }> {
+    const { privateKey, publicKey } = await generateKeyPair('ed25519', {
+      publicKeyEncoding: { type: 'spki', format: 'pem' },
+      privateKeyEncoding: { type: 'pkcs8', format: 'pem' },
+    });
+
+    return { privateKey, publicKey };
+  }
+
   // Store a DKIM key pair - uses storage manager if available, else disk
   public async storeDKIMKeys(
     privateKey: string,
@@ -176,8 +186,11 @@ export class DKIMCreator {
       .replace(pemFooter, '')
       .replace(/\n/g, '');
 
+    // Detect key type from PEM header
+    const keyAlgo = keys.privateKey.includes('ED25519') || keys.publicKey.length < 200 ? 'ed25519' : 'rsa';
+
     // Now generate the DKIM DNS TXT record
-    const dnsRecordValue = `v=DKIM1; h=sha256; k=rsa; p=${keyContents}`;
+    const dnsRecordValue = `v=DKIM1; h=sha256; k=${keyAlgo}; p=${keyContents}`;
 
     return {
       name: `mta._domainkey.${domainArg}`,
@@ -375,8 +388,11 @@ export class DKIMCreator {
       .replace(pemFooter, '')
       .replace(/\n/g, '');
 
+    // Detect key type from PEM header
+    const keyAlgo = keys.privateKey.includes('ED25519') || keys.publicKey.length < 200 ? 'ed25519' : 'rsa';
+
     // Generate the DKIM DNS TXT record
-    const dnsRecordValue = `v=DKIM1; h=sha256; k=rsa; p=${keyContents}`;
+    const dnsRecordValue = `v=DKIM1; h=sha256; k=${keyAlgo}; p=${keyContents}`;
 
     return {
       name: `${selector}._domainkey.${domain}`,

ts/mail/security/classes.dkimverifier.ts

@@ -1,86 +0,0 @@
-import { logger } from '../../logger.js';
-import { SecurityLogger, SecurityLogLevel, SecurityEventType } from '../../security/index.js';
-import { RustSecurityBridge } from '../../security/classes.rustsecuritybridge.js';
-
-/**
- * Result of a DKIM verification
- */
-export interface IDkimVerificationResult {
-  isValid: boolean;
-  domain?: string;
-  selector?: string;
-  status?: string;
-  details?: any;
-  errorMessage?: string;
-  signatureFields?: Record<string, string>;
-}
-
-/**
- * DKIM verifier — delegates to the Rust security bridge.
- */
-export class DKIMVerifier {
-  constructor() {}
-
-  /**
-   * Verify DKIM signature for an email via Rust bridge
-   */
-  public async verify(
-    emailData: string,
-    options: {
-      useCache?: boolean;
-      returnDetails?: boolean;
-    } = {}
-  ): Promise<IDkimVerificationResult> {
-    try {
-      const bridge = RustSecurityBridge.getInstance();
-      const results = await bridge.verifyDkim(emailData);
-      const first = results[0];
-
-      const result: IDkimVerificationResult = {
-        isValid: first?.is_valid ?? false,
-        domain: first?.domain ?? undefined,
-        selector: first?.selector ?? undefined,
-        status: first?.status ?? 'none',
-        details: options.returnDetails ? results : undefined,
-      };
-
-      SecurityLogger.getInstance().logEvent({
-        level: result.isValid ? SecurityLogLevel.INFO : SecurityLogLevel.WARN,
-        type: SecurityEventType.DKIM,
-        message: `DKIM verification ${result.isValid ? 'passed' : 'failed'} for domain ${result.domain || 'unknown'}`,
-        details: { selector: result.selector, status: result.status },
-        domain: result.domain || 'unknown',
-        success: result.isValid
-      });
-
-      logger.log(result.isValid ? 'info' : 'warn',
-        `DKIM verification: ${result.status} for domain ${result.domain || 'unknown'}`);
-
-      return result;
-    } catch (error) {
-      logger.log('error', `DKIM verification failed: ${error.message}`);
-
-      SecurityLogger.getInstance().logEvent({
-        level: SecurityLogLevel.ERROR,
-        type: SecurityEventType.DKIM,
-        message: `DKIM verification error`,
-        details: { error: error.message },
-        success: false
-      });
-
-      return {
-        isValid: false,
-        status: 'temperror',
-        errorMessage: `Verification error: ${error.message}`
-      };
-    }
-  }
-
-  /** No-op — Rust bridge handles its own caching */
-  public clearCache(): void {}
-
-  /** Always 0 — cache is managed by the Rust side */
-  public getCacheSize(): number {
-    return 0;
-  }
-}

ts/mail/security/classes.dmarcverifier.ts

@@ -1,475 +0,0 @@
-import { logger } from '../../logger.js';
-import { SecurityLogger, SecurityLogLevel, SecurityEventType } from '../../security/index.js';
-import type { Email } from '../core/classes.email.js';
-
-/**
- * DMARC policy types
- */
-export enum DmarcPolicy {
-  NONE = 'none',
-  QUARANTINE = 'quarantine',
-  REJECT = 'reject'
-}
-
-/**
- * DMARC alignment modes
- */
-export enum DmarcAlignment {
-  RELAXED = 'r',
-  STRICT = 's'
-}
-
-/**
- * DMARC record fields
- */
-export interface DmarcRecord {
-  // Required fields
-  version: string;
-  policy: DmarcPolicy;
-  
-  // Optional fields
-  subdomainPolicy?: DmarcPolicy;
-  pct?: number;
-  adkim?: DmarcAlignment;
-  aspf?: DmarcAlignment;
-  reportInterval?: number;
-  failureOptions?: string;
-  reportUriAggregate?: string[];
-  reportUriForensic?: string[];
-}
-
-/**
- * DMARC verification result
- */
-export interface DmarcResult {
-  hasDmarc: boolean;
-  record?: DmarcRecord;
-  spfDomainAligned: boolean;
-  dkimDomainAligned: boolean;
-  spfPassed: boolean;
-  dkimPassed: boolean;
-  policyEvaluated: DmarcPolicy;
-  actualPolicy: DmarcPolicy;
-  appliedPercentage: number;
-  action: 'pass' | 'quarantine' | 'reject';
-  details: string;
-  error?: string;
-}
-
-/**
- * Class for verifying and enforcing DMARC policies
- */
-export class DmarcVerifier {
-  // DNS Manager reference for verifying records
-  private dnsManager?: any;
-  
-  constructor(dnsManager?: any) {
-    this.dnsManager = dnsManager;
-  }
-  
-  /**
-   * Parse a DMARC record from a TXT record string
-   * @param record DMARC TXT record string
-   * @returns Parsed DMARC record or null if invalid
-   */
-  public parseDmarcRecord(record: string): DmarcRecord | null {
-    if (!record.startsWith('v=DMARC1')) {
-      return null;
-    }
-    
-    try {
-      // Initialize record with default values
-      const dmarcRecord: DmarcRecord = {
-        version: 'DMARC1',
-        policy: DmarcPolicy.NONE,
-        pct: 100,
-        adkim: DmarcAlignment.RELAXED,
-        aspf: DmarcAlignment.RELAXED
-      };
-      
-      // Split the record into tag/value pairs
-      const parts = record.split(';').map(part => part.trim());
-      
-      for (const part of parts) {
-        if (!part || !part.includes('=')) continue;
-        
-        const [tag, value] = part.split('=').map(p => p.trim());
-        
-        // Process based on tag
-        switch (tag.toLowerCase()) {
-          case 'v':
-            dmarcRecord.version = value;
-            break;
-          case 'p':
-            dmarcRecord.policy = value as DmarcPolicy;
-            break;
-          case 'sp':
-            dmarcRecord.subdomainPolicy = value as DmarcPolicy;
-            break;
-          case 'pct':
-            const pctValue = parseInt(value, 10);
-            if (!isNaN(pctValue) && pctValue >= 0 && pctValue <= 100) {
-              dmarcRecord.pct = pctValue;
-            }
-            break;
-          case 'adkim':
-            dmarcRecord.adkim = value as DmarcAlignment;
-            break;
-          case 'aspf':
-            dmarcRecord.aspf = value as DmarcAlignment;
-            break;
-          case 'ri':
-            const interval = parseInt(value, 10);
-            if (!isNaN(interval) && interval > 0) {
-              dmarcRecord.reportInterval = interval;
-            }
-            break;
-          case 'fo':
-            dmarcRecord.failureOptions = value;
-            break;
-          case 'rua':
-            dmarcRecord.reportUriAggregate = value.split(',').map(uri => {
-              if (uri.startsWith('mailto:')) {
-                return uri.substring(7).trim();
-              }
-              return uri.trim();
-            });
-            break;
-          case 'ruf':
-            dmarcRecord.reportUriForensic = value.split(',').map(uri => {
-              if (uri.startsWith('mailto:')) {
-                return uri.substring(7).trim();
-              }
-              return uri.trim();
-            });
-            break;
-        }
-      }
-      
-      // Ensure subdomain policy is set if not explicitly provided
-      if (!dmarcRecord.subdomainPolicy) {
-        dmarcRecord.subdomainPolicy = dmarcRecord.policy;
-      }
-      
-      return dmarcRecord;
-    } catch (error) {
-      logger.log('error', `Error parsing DMARC record: ${error.message}`, {
-        record,
-        error: error.message
-      });
-      return null;
-    }
-  }
-  
-  /**
-   * Check if domains are aligned according to DMARC policy
-   * @param headerDomain Domain from header (From)
-   * @param authDomain Domain from authentication (SPF, DKIM)
-   * @param alignment Alignment mode
-   * @returns Whether the domains are aligned
-   */
-  private isDomainAligned(
-    headerDomain: string,
-    authDomain: string,
-    alignment: DmarcAlignment
-  ): boolean {
-    if (!headerDomain || !authDomain) {
-      return false;
-    }
-    
-    // For strict alignment, domains must match exactly
-    if (alignment === DmarcAlignment.STRICT) {
-      return headerDomain.toLowerCase() === authDomain.toLowerCase();
-    }
-    
-    // For relaxed alignment, the authenticated domain must be a subdomain of the header domain
-    // or the same as the header domain
-    const headerParts = headerDomain.toLowerCase().split('.');
-    const authParts = authDomain.toLowerCase().split('.');
-    
-    // Ensures we have at least two parts (domain and TLD)
-    if (headerParts.length < 2 || authParts.length < 2) {
-      return false;
-    }
-    
-    // Get organizational domain (last two parts)
-    const headerOrgDomain = headerParts.slice(-2).join('.');
-    const authOrgDomain = authParts.slice(-2).join('.');
-    
-    return headerOrgDomain === authOrgDomain;
-  }
-  
-  /**
-   * Extract domain from an email address
-   * @param email Email address
-   * @returns Domain part of the email
-   */
-  private getDomainFromEmail(email: string): string {
-    if (!email) return '';
-    
-    // Handle name + email format: "John Doe <john@example.com>"
-    const matches = email.match(/<([^>]+)>/);
-    const address = matches ? matches[1] : email;
-    
-    const parts = address.split('@');
-    return parts.length > 1 ? parts[1] : '';
-  }
-  
-  /**
-   * Check if DMARC verification should be applied based on percentage
-   * @param record DMARC record
-   * @returns Whether DMARC verification should be applied
-   */
-  private shouldApplyDmarc(record: DmarcRecord): boolean {
-    if (record.pct === undefined || record.pct === 100) {
-      return true;
-    }
-    
-    // Apply DMARC randomly based on percentage
-    const random = Math.floor(Math.random() * 100) + 1;
-    return random <= record.pct;
-  }
-  
-  /**
-   * Determine the action to take based on DMARC policy
-   * @param policy DMARC policy
-   * @returns Action to take
-   */
-  private determineAction(policy: DmarcPolicy): 'pass' | 'quarantine' | 'reject' {
-    switch (policy) {
-      case DmarcPolicy.REJECT:
-        return 'reject';
-      case DmarcPolicy.QUARANTINE:
-        return 'quarantine';
-      case DmarcPolicy.NONE:
-      default:
-        return 'pass';
-    }
-  }
-  
-  /**
-   * Verify DMARC for an incoming email
-   * @param email Email to verify
-   * @param spfResult SPF verification result
-   * @param dkimResult DKIM verification result
-   * @returns DMARC verification result
-   */
-  public async verify(
-    email: Email,
-    spfResult: { domain: string; result: boolean },
-    dkimResult: { domain: string; result: boolean }
-  ): Promise<DmarcResult> {
-    const securityLogger = SecurityLogger.getInstance();
-    
-    // Initialize result
-    const result: DmarcResult = {
-      hasDmarc: false,
-      spfDomainAligned: false,
-      dkimDomainAligned: false,
-      spfPassed: spfResult.result,
-      dkimPassed: dkimResult.result,
-      policyEvaluated: DmarcPolicy.NONE,
-      actualPolicy: DmarcPolicy.NONE,
-      appliedPercentage: 100,
-      action: 'pass',
-      details: 'DMARC not configured'
-    };
-    
-    try {
-      // Extract From domain
-      const fromHeader = email.getFromEmail();
-      const fromDomain = this.getDomainFromEmail(fromHeader);
-      
-      if (!fromDomain) {
-        result.error = 'Invalid From domain';
-        return result;
-      }
-      
-      // Check alignment
-      result.spfDomainAligned = this.isDomainAligned(
-        fromDomain,
-        spfResult.domain,
-        DmarcAlignment.RELAXED
-      );
-      
-      result.dkimDomainAligned = this.isDomainAligned(
-        fromDomain,
-        dkimResult.domain,
-        DmarcAlignment.RELAXED
-      );
-      
-      // Lookup DMARC record
-      const dmarcVerificationResult = this.dnsManager ? 
-        await this.dnsManager.verifyDmarcRecord(fromDomain) :
-        { found: false, valid: false, error: 'DNS Manager not available' };
-      
-      // If DMARC record exists and is valid
-      if (dmarcVerificationResult.found && dmarcVerificationResult.valid) {
-        result.hasDmarc = true;
-        
-        // Parse DMARC record
-        const parsedRecord = this.parseDmarcRecord(dmarcVerificationResult.value);
-        
-        if (parsedRecord) {
-          result.record = parsedRecord;
-          result.actualPolicy = parsedRecord.policy;
-          result.appliedPercentage = parsedRecord.pct || 100;
-          
-          // Override alignment modes if specified in record
-          if (parsedRecord.adkim) {
-            result.dkimDomainAligned = this.isDomainAligned(
-              fromDomain,
-              dkimResult.domain,
-              parsedRecord.adkim
-            );
-          }
-          
-          if (parsedRecord.aspf) {
-            result.spfDomainAligned = this.isDomainAligned(
-              fromDomain,
-              spfResult.domain,
-              parsedRecord.aspf
-            );
-          }
-          
-          // Determine DMARC compliance
-          const spfAligned = result.spfPassed && result.spfDomainAligned;
-          const dkimAligned = result.dkimPassed && result.dkimDomainAligned;
-          
-          // Email passes DMARC if either SPF or DKIM passes with alignment
-          const dmarcPass = spfAligned || dkimAligned;
-          
-          // Use record percentage to determine if policy should be applied
-          const applyPolicy = this.shouldApplyDmarc(parsedRecord);
-          
-          if (!dmarcPass) {
-            // DMARC failed, apply policy
-            result.policyEvaluated = applyPolicy ? parsedRecord.policy : DmarcPolicy.NONE;
-            result.action = this.determineAction(result.policyEvaluated);
-            result.details = `DMARC failed: SPF aligned=${spfAligned}, DKIM aligned=${dkimAligned}, policy=${result.policyEvaluated}`;
-          } else {
-            result.policyEvaluated = DmarcPolicy.NONE;
-            result.action = 'pass';
-            result.details = `DMARC passed: SPF aligned=${spfAligned}, DKIM aligned=${dkimAligned}`;
-          }
-        } else {
-          result.error = 'Invalid DMARC record format';
-          result.details = 'DMARC record invalid';
-        }
-      } else {
-        // No DMARC record found or invalid
-        result.details = dmarcVerificationResult.error || 'No DMARC record found';
-      }
-      
-      // Log the DMARC verification
-      securityLogger.logEvent({
-        level: result.action === 'pass' ? SecurityLogLevel.INFO : SecurityLogLevel.WARN,
-        type: SecurityEventType.DMARC,
-        message: result.details,
-        domain: fromDomain,
-        details: {
-          fromDomain,
-          spfDomain: spfResult.domain,
-          dkimDomain: dkimResult.domain,
-          spfPassed: result.spfPassed,
-          dkimPassed: result.dkimPassed,
-          spfAligned: result.spfDomainAligned,
-          dkimAligned: result.dkimDomainAligned,
-          dmarcPolicy: result.policyEvaluated,
-          action: result.action
-        },
-        success: result.action === 'pass'
-      });
-      
-      return result;
-    } catch (error) {
-      logger.log('error', `Error verifying DMARC: ${error.message}`, {
-        error: error.message,
-        emailId: email.getMessageId()
-      });
-      
-      result.error = `DMARC verification error: ${error.message}`;
-      
-      // Log error
-      securityLogger.logEvent({
-        level: SecurityLogLevel.ERROR,
-        type: SecurityEventType.DMARC,
-        message: `DMARC verification failed with error`,
-        details: {
-          error: error.message,
-          emailId: email.getMessageId()
-        },
-        success: false
-      });
-      
-      return result;
-    }
-  }
-  
-  /**
-   * Apply DMARC policy to an email
-   * @param email Email to apply policy to
-   * @param dmarcResult DMARC verification result
-   * @returns Whether the email should be accepted
-   */
-  public applyPolicy(email: Email, dmarcResult: DmarcResult): boolean {
-    // Apply action based on DMARC verification result
-    switch (dmarcResult.action) {
-      case 'reject':
-        // Reject the email
-        email.mightBeSpam = true;
-        logger.log('warn', `Email rejected due to DMARC policy: ${dmarcResult.details}`, {
-          emailId: email.getMessageId(),
-          from: email.getFromEmail(),
-          subject: email.subject
-        });
-        return false;
-        
-      case 'quarantine':
-        // Quarantine the email (mark as spam)
-        email.mightBeSpam = true;
-        
-        // Add spam header
-        if (!email.headers['X-Spam-Flag']) {
-          email.headers['X-Spam-Flag'] = 'YES';
-        }
-        
-        // Add DMARC reason header
-        email.headers['X-DMARC-Result'] = dmarcResult.details;
-        
-        logger.log('warn', `Email quarantined due to DMARC policy: ${dmarcResult.details}`, {
-          emailId: email.getMessageId(),
-          from: email.getFromEmail(),
-          subject: email.subject
-        });
-        return true;
-        
-      case 'pass':
-      default:
-        // Accept the email
-        // Add DMARC result header for information
-        email.headers['X-DMARC-Result'] = dmarcResult.details;
-        return true;
-    }
-  }
-  
-  /**
-   * End-to-end DMARC verification and policy application
-   * This method should be called after SPF and DKIM verification
-   * @param email Email to verify
-   * @param spfResult SPF verification result
-   * @param dkimResult DKIM verification result
-   * @returns Whether the email should be accepted
-   */
-  public async verifyAndApply(
-    email: Email,
-    spfResult: { domain: string; result: boolean },
-    dkimResult: { domain: string; result: boolean }
-  ): Promise<boolean> {
-    // Verify DMARC
-    const dmarcResult = await this.verify(email, spfResult, dkimResult);
-    
-    // Apply DMARC policy
-    return this.applyPolicy(email, dmarcResult);
-  }
-}

ts/mail/security/classes.spfverifier.ts

@@ -1,8 +1,4 @@
-import * as plugins from '../../plugins.js';
 import { logger } from '../../logger.js';
-import { SecurityLogger, SecurityLogLevel, SecurityEventType } from '../../security/index.js';
-import { RustSecurityBridge } from '../../security/classes.rustsecuritybridge.js';
-import type { Email } from '../core/classes.email.js';
 
 /**
  * SPF result qualifiers
@@ -127,107 +123,4 @@ export class SpfVerifier {
       return null;
     }
   }
-
-  /**
-   * Verify SPF for a given email — delegates to Rust bridge
-   */
-  public async verify(
-    email: Email,
-    ip: string,
-    heloDomain: string
-  ): Promise<SpfResult> {
-    const securityLogger = SecurityLogger.getInstance();
-    const mailFrom = email.from || '';
-    const domain = mailFrom.split('@')[1] || '';
-
-    try {
-      const bridge = RustSecurityBridge.getInstance();
-      const result = await bridge.checkSpf({
-        ip,
-        heloDomain,
-        hostname: plugins.os.hostname(),
-        mailFrom,
-      });
-
-      const spfResult: SpfResult = {
-        result: result.result as SpfResult['result'],
-        domain: result.domain,
-        ip: result.ip,
-        explanation: result.explanation ?? undefined,
-      };
-
-      securityLogger.logEvent({
-        level: spfResult.result === 'pass' ? SecurityLogLevel.INFO :
-               (spfResult.result === 'fail' ? SecurityLogLevel.WARN : SecurityLogLevel.INFO),
-        type: SecurityEventType.SPF,
-        message: `SPF ${spfResult.result} for ${spfResult.domain} from IP ${ip}`,
-        domain: spfResult.domain,
-        details: { ip, heloDomain, result: spfResult.result, explanation: spfResult.explanation },
-        success: spfResult.result === 'pass'
-      });
-
-      return spfResult;
-    } catch (error) {
-      logger.log('error', `SPF verification error: ${error.message}`, { domain, ip, error: error.message });
-
-      securityLogger.logEvent({
-        level: SecurityLogLevel.ERROR,
-        type: SecurityEventType.SPF,
-        message: `SPF verification error for ${domain}`,
-        domain,
-        details: { ip, error: error.message },
-        success: false
-      });
-
-      return {
-        result: 'temperror',
-        explanation: `Error verifying SPF: ${error.message}`,
-        domain,
-        ip,
-        error: error.message
-      };
-    }
-  }
-
-  /**
-   * Check if email passes SPF verification and apply headers
-   */
-  public async verifyAndApply(
-    email: Email,
-    ip: string,
-    heloDomain: string
-  ): Promise<boolean> {
-    const result = await this.verify(email, ip, heloDomain);
-
-    email.headers['Received-SPF'] = `${result.result} (${result.domain}: ${result.explanation || ''}) client-ip=${ip}; envelope-from=${email.getEnvelopeFrom()}; helo=${heloDomain};`;
-
-    switch (result.result) {
-      case 'fail':
-        email.mightBeSpam = true;
-        logger.log('warn', `SPF failed for ${result.domain} from ${ip}: ${result.explanation}`);
-        return false;
-
-      case 'softfail':
-        email.mightBeSpam = true;
-        logger.log('info', `SPF softfailed for ${result.domain} from ${ip}: ${result.explanation}`);
-        return true;
-
-      case 'neutral':
-      case 'none':
-        logger.log('info', `SPF ${result.result} for ${result.domain} from ${ip}: ${result.explanation}`);
-        return true;
-
-      case 'pass':
-        logger.log('info', `SPF passed for ${result.domain} from ${ip}: ${result.explanation}`);
-        return true;
-
-      case 'temperror':
-      case 'permerror':
-        logger.log('error', `SPF error for ${result.domain} from ${ip}: ${result.explanation}`);
-        return true;
-
-      default:
-        return true;
-    }
-  }
 }

ts/mail/security/index.ts

@@ -1,5 +1,3 @@
 // Email security components
 export * from './classes.dkimcreator.js';
-export * from './classes.dkimverifier.js';
-export * from './classes.dmarcverifier.js';
 export * from './classes.spfverifier.js';

ts/security/classes.rustsecuritybridge.ts

@@ -95,11 +95,12 @@ interface ISmtpSendOptions {
   domain?: string;
   auth?: { user: string; pass: string; method?: string };
   email: IOutboundEmail;
-  dkim?: { domain: string; selector: string; privateKey: string };
+  dkim?: { domain: string; selector: string; privateKey: string; keyType?: string };
   connectionTimeoutSecs?: number;
   socketTimeoutSecs?: number;
   poolKey?: string;
   maxPoolConnections?: number;
+  tlsOpportunistic?: boolean;
 }
 
 interface ISmtpSendRawOptions {
@@ -147,6 +148,7 @@ interface ISmtpServerConfig {
   securePort?: number;
   tlsCertPem?: string;
   tlsKeyPem?: string;
+  additionalTlsCerts?: Array<{ domains: string[]; certPem: string; keyPem: string }>;
   maxMessageSize?: number;
   maxConnections?: number;
   maxRecipients?: number;
@@ -193,6 +195,13 @@ interface IAuthRequestEvent {
   remoteAddr: string;
 }
 
+interface IScramCredentialRequestEvent {
+  correlationId: string;
+  sessionId: string;
+  username: string;
+  remoteAddr: string;
+}
+
 /**
  * Type-safe command map for the mailer-bin IPC bridge.
  */
@@ -222,7 +231,7 @@ type TMailerCommands = {
     result: IDkimVerificationResult[];
   };
   signDkim: {
-    params: { rawMessage: string; domain: string; selector?: string; privateKey: string };
+    params: { rawMessage: string; domain: string; selector?: string; privateKey: string; keyType?: string };
     result: { header: string; signedMessage: string };
   };
   checkSpf: {
@@ -273,6 +282,17 @@ type TMailerCommands = {
     };
     result: { resolved: boolean };
   };
+  scramCredentialResult: {
+    params: {
+      correlationId: string;
+      found: boolean;
+      salt?: string;
+      iterations?: number;
+      storedKey?: string;
+      serverKey?: string;
+    };
+    result: { resolved: boolean };
+  };
   configureRateLimits: {
     params: IRateLimitConfig;
     result: { configured: boolean };
@@ -706,12 +726,13 @@ export class RustSecurityBridge extends EventEmitter {
     return this.bridge.sendCommand('verifyDkim', { rawMessage });
   }
 
-  /** Sign an email with DKIM. */
+  /** Sign an email with DKIM (RSA or Ed25519). */
   public async signDkim(opts: {
     rawMessage: string;
     domain: string;
     selector?: string;
     privateKey: string;
+    keyType?: string;
   }): Promise<{ header: string; signedMessage: string }> {
     this.ensureRunning();
     return this.bridge.sendCommand('signDkim', opts);
@@ -829,6 +850,22 @@ export class RustSecurityBridge extends EventEmitter {
     await this.bridge.sendCommand('authResult', opts);
   }
 
+  /**
+   * Send SCRAM credentials back to the Rust SMTP server.
+   * Values (salt, storedKey, serverKey) must be base64-encoded.
+   */
+  public async sendScramCredentialResult(opts: {
+    correlationId: string;
+    found: boolean;
+    salt?: string;
+    iterations?: number;
+    storedKey?: string;
+    serverKey?: string;
+  }): Promise<void> {
+    this.ensureRunning();
+    await this.bridge.sendCommand('scramCredentialResult', opts);
+  }
+
   /** Update rate limit configuration at runtime. */
   public async configureRateLimits(config: IRateLimitConfig): Promise<void> {
     this.ensureRunning();
@@ -855,6 +892,14 @@ export class RustSecurityBridge extends EventEmitter {
     this.bridge.on('management:authRequest', handler);
   }
 
+  /**
+   * Register a handler for scramCredentialRequest events from the Rust SMTP server.
+   * The handler must call sendScramCredentialResult() with the correlationId.
+   */
+  public onScramCredentialRequest(handler: (data: IScramCredentialRequestEvent) => void): void {
+    this.bridge.on('management:scramCredentialRequest', handler);
+  }
+
   /** Remove an emailReceived event handler. */
   public offEmailReceived(handler: (data: IEmailReceivedEvent) => void): void {
     this.bridge.off('management:emailReceived', handler);
@@ -864,6 +909,11 @@ export class RustSecurityBridge extends EventEmitter {
   public offAuthRequest(handler: (data: IAuthRequestEvent) => void): void {
     this.bridge.off('management:authRequest', handler);
   }
+
+  /** Remove a scramCredentialRequest event handler. */
+  public offScramCredentialRequest(handler: (data: IScramCredentialRequestEvent) => void): void {
+    this.bridge.off('management:scramCredentialRequest', handler);
+  }
 }
 
 // Re-export interfaces for consumers
@@ -882,6 +932,7 @@ export type {
   IEmailData,
   IEmailReceivedEvent,
   IAuthRequestEvent,
+  IScramCredentialRequestEvent,
   IOutboundEmail,
   ISmtpSendResult,
   ISmtpSendOptions,