fix(vpn): resolve VPN-gated route domains into per-client AllowedIPs with cached DNS lookups

changelog.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## 2026-03-31 - 11.21.1 - fix(vpn)
+resolve VPN-gated route domains into per-client AllowedIPs with cached DNS lookups
+
+- Derive WireGuard AllowedIPs from DNS A records of matched vpn.required route domains instead of only configured public proxy IPs.
+- Cache resolved domain IPs for 5 minutes and fall back to stale results on DNS lookup failures.
+- Make per-client AllowedIPs generation asynchronous throughout VPN config export and regeneration flows.
+
 ## 2026-03-31 - 11.21.0 - feat(vpn)
 add tag-aware WireGuard AllowedIPs for VPN-gated routes
 

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@serve.zone/dcrouter',
-  version: '11.21.0',
+  version: '11.21.1',
   description: 'A multifaceted routing service handling mail and SMS delivery functions.'
 }

ts/classes.dcrouter.ts

@@ -2105,34 +2105,35 @@ export class DcRouter {
         // Re-apply routes so tag-based ipAllowLists get updated
         this.routeConfigManager?.applyRoutes();
       },
-      getClientAllowedIPs: (clientTags: string[]) => {
+      getClientAllowedIPs: async (clientTags: string[]) => {
         const subnet = this.options.vpnConfig?.subnet || '10.8.0.0/24';
         const ips = new Set<string>([subnet]);
 
-        // Determine the server's public-facing IP(s) that VPN-gated domains resolve to
+        // Check routes for VPN-gated tag match and collect domains
-        const publicIPs: string[] = [];
-        if (this.options.proxyIps?.length) {
-          publicIPs.push(...this.options.proxyIps);
-        }
-        if (this.options.publicIp) {
-          publicIPs.push(this.options.publicIp);
-        } else if (this.detectedPublicIp) {
-          publicIPs.push(this.detectedPublicIp);
-        }
-        if (!publicIPs.length) return [...ips];
-
-        // Check routes for VPN-gated tag match
         const routes = this.options.smartProxyConfig?.routes || [];
+        const domainsToResolve = new Set<string>();
         for (const route of routes) {
           const dcRoute = route as import('../ts_interfaces/data/remoteingress.js').IDcRouterRouteConfig;
           if (!dcRoute.vpn?.required) continue;
 
           const routeTags = dcRoute.vpn.allowedServerDefinedClientTags;
           if (!routeTags?.length || clientTags.some(t => routeTags.includes(t))) {
-            for (const ip of publicIPs) {
+            // Collect domains from this route
-              ips.add(`${ip}/32`);
+            const domains = (route.match as any)?.domains;
+            if (Array.isArray(domains)) {
+              for (const d of domains) {
+                // Strip wildcard prefix for DNS resolution (*.example.com → example.com)
+                domainsToResolve.add(d.replace(/^\*\./, ''));
+              }
             }
-            break; // All routes resolve to the same server IPs
+          }
+        }
+
+        // Resolve DNS A records for matched domains (with caching)
+        for (const domain of domainsToResolve) {
+          const resolvedIps = await this.resolveVpnDomainIPs(domain);
+          for (const ip of resolvedIps) {
+            ips.add(`${ip}/32`);
           }
         }
 
@@ -2143,6 +2144,28 @@ export class DcRouter {
     await this.vpnManager.start();
   }
 
+  /** Cache for DNS-resolved IPs of VPN-gated domains. TTL: 5 minutes. */
+  private vpnDomainIpCache = new Map<string, { ips: string[]; expiresAt: number }>();
+
+  /**
+   * Resolve a domain's A record(s) for VPN AllowedIPs, with a 5-minute cache.
+   */
+  private async resolveVpnDomainIPs(domain: string): Promise<string[]> {
+    const cached = this.vpnDomainIpCache.get(domain);
+    if (cached && cached.expiresAt > Date.now()) {
+      return cached.ips;
+    }
+    try {
+      const { promises: dnsPromises } = await import('dns');
+      const ips = await dnsPromises.resolve4(domain);
+      this.vpnDomainIpCache.set(domain, { ips, expiresAt: Date.now() + 5 * 60 * 1000 });
+      return ips;
+    } catch (err) {
+      logger.log('warn', `VPN: Failed to resolve ${domain} for AllowedIPs: ${(err as Error).message}`);
+      return cached?.ips || []; // Return stale cache on failure, or empty
+    }
+  }
+
   /**
    * Inject VPN security into routes that have vpn.required === true.
    * Adds the VPN subnet to security.ipAllowList so only VPN clients can access them.

ts/vpn/classes.vpn-manager.ts

@@ -32,7 +32,7 @@ export interface IVpnManagerConfig {
   /** Compute per-client AllowedIPs based on the client's server-defined tags.
    *  Called at config generation time (create/export). Returns CIDRs for WireGuard AllowedIPs.
    *  When not set, defaults to [subnet]. */
-  getClientAllowedIPs?: (clientTags: string[]) => string[];
+  getClientAllowedIPs?: (clientTags: string[]) => Promise<string[]>;
 }
 
 interface IPersistedServerKeys {
@@ -196,7 +196,7 @@ export class VpnManager {
 
     // Override AllowedIPs with per-client values based on tag-matched routes
     if (this.config.getClientAllowedIPs && bundle.wireguardConfig) {
-      const allowedIPs = this.config.getClientAllowedIPs(opts.serverDefinedClientTags || []);
+      const allowedIPs = await this.config.getClientAllowedIPs(opts.serverDefinedClientTags || []);
       bundle.wireguardConfig = bundle.wireguardConfig.replace(
         /AllowedIPs\s*=\s*.+/,
         `AllowedIPs = ${allowedIPs.join(', ')}`,
@@ -317,7 +317,7 @@ export class VpnManager {
       // Override AllowedIPs with per-client values based on tag-matched routes
       if (this.config.getClientAllowedIPs) {
         const clientTags = persisted?.serverDefinedClientTags || [];
-        const allowedIPs = this.config.getClientAllowedIPs(clientTags);
+        const allowedIPs = await this.config.getClientAllowedIPs(clientTags);
         config = config.replace(
           /AllowedIPs\s*=\s*.+/,
           `AllowedIPs = ${allowedIPs.join(', ')}`,

ts_web/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@serve.zone/dcrouter',
-  version: '11.21.0',
+  version: '11.21.1',
   description: 'A multifaceted routing service handling mail and SMS delivery functions.'
 }