feat(PortProxy): Add feature to preserve original client IP through chained proxies

changelog.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## 2025-02-21 - 3.6.0 - feat(PortProxy)
+Add feature to preserve original client IP through chained proxies
+
+- Added support to bind local address in PortProxy to preserve original client IP.
+- Implemented test for chained proxies to ensure client IP is preserved.
+
 ## 2025-02-21 - 3.5.0 - feat(PortProxy)
 Enhance PortProxy to support domain-specific target IPs
 

test/test.portproxy.ts

@@ -175,6 +175,37 @@ tap.test('should stop port proxy', async () => {
 });
 
 // Cleanup
+tap.test('should preserve client IP through chained proxies', async () => {
+  // Create two proxies in chain
+  const firstProxy = new PortProxy({
+    fromPort: PROXY_PORT + 4,
+    toPort: PROXY_PORT + 5,  // Point to second proxy
+    toHost: 'localhost',
+    domains: [],
+    sniEnabled: false,
+    defaultAllowedIPs: ['127.0.0.1']
+  });
+
+  const secondProxy = new PortProxy({
+    fromPort: PROXY_PORT + 5,
+    toPort: TEST_SERVER_PORT,
+    toHost: 'localhost',
+    domains: [],
+    sniEnabled: false,
+    defaultAllowedIPs: ['127.0.0.1']
+  });
+
+  await secondProxy.start();
+  await firstProxy.start();
+
+  // Connect through the chain
+  const response = await createTestClient(PROXY_PORT + 4, TEST_DATA);
+  expect(response).toEqual(`Echo: ${TEST_DATA}`);
+
+  await firstProxy.stop();
+  await secondProxy.stop();
+});
+
 tap.test('cleanup port proxy test environment', async () => {
   await new Promise<void>((resolve) => testServer.close(() => resolve()));
 });

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartproxy',
-  version: '3.5.0',
+  version: '3.6.0',
   description: 'a proxy for handling high workloads of proxying'
 }

ts/smartproxy.portproxy.ts

@@ -123,9 +123,11 @@ export class PortProxy {
       const domainConfig = serverName ? findMatchingDomain(serverName) : undefined;
       const targetHost = domainConfig?.targetIP || this.settings.toHost!;
       
+      // Create connection with IP binding to preserve original client IP
       const to = plugins.net.createConnection({
         host: targetHost,
         port: this.settings.toPort,
+        localAddress: remoteIP.replace('::ffff:', ''), // Remove IPv6 mapping if present
       });
       console.log(`Connection established: ${remoteIP} -> ${targetHost}:${this.settings.toPort}${serverName ? ` (SNI: ${serverName})` : ''}`);
       from.setTimeout(120000);