feat(PortProxy): Enhance PortProxy to support domain-specific target IPs

test/test.portproxy.ts

@@ -95,6 +95,54 @@ tap.test('should forward TCP connections to custom host', async () => {
   await customHostProxy.stop();
 });
 
+tap.test('should forward connections based on domain-specific target IP', async () => {
+  // Create a second test server on a different port
+  const TEST_SERVER_PORT_2 = TEST_SERVER_PORT + 100;
+  const testServer2 = await createTestServer(TEST_SERVER_PORT_2);
+
+  // Create a proxy with domain-specific target IPs
+  const domainProxy = new PortProxy({
+    fromPort: PROXY_PORT + 2,
+    toPort: TEST_SERVER_PORT,  // default port
+    toHost: 'localhost',       // default host
+    domains: [{
+      domain: 'domain1.test',
+      allowedIPs: ['127.0.0.1'],
+      targetIP: '127.0.0.1'
+    }, {
+      domain: 'domain2.test',
+      allowedIPs: ['127.0.0.1'],
+      targetIP: 'localhost'
+    }],
+    sniEnabled: false, // We'll test without SNI first since this is a TCP proxy test
+    defaultAllowedIPs: ['127.0.0.1']
+  });
+
+  await domainProxy.start();
+
+  // Test default connection (should use default host)
+  const response1 = await createTestClient(PROXY_PORT + 2, TEST_DATA);
+  expect(response1).toEqual(`Echo: ${TEST_DATA}`);
+
+  // Create another proxy with different default host
+  const domainProxy2 = new PortProxy({
+    fromPort: PROXY_PORT + 3,
+    toPort: TEST_SERVER_PORT,
+    toHost: '127.0.0.1',
+    domains: [],
+    sniEnabled: false,
+    defaultAllowedIPs: ['127.0.0.1']
+  });
+
+  await domainProxy2.start();
+  const response2 = await createTestClient(PROXY_PORT + 3, TEST_DATA);
+  expect(response2).toEqual(`Echo: ${TEST_DATA}`);
+
+  await domainProxy.stop();
+  await domainProxy2.stop();
+  await new Promise<void>((resolve) => testServer2.close(() => resolve()));
+});
+
 tap.test('should handle multiple concurrent connections', async () => {
   const concurrentRequests = 5;
   const requests = Array(concurrentRequests).fill(null).map((_, i) =>