diff --git a/cmd/outline-ss-server/main.go b/cmd/outline-ss-server/main.go
index 2c1da142..87860df7 100644
--- a/cmd/outline-ss-server/main.go
+++ b/cmd/outline-ss-server/main.go
@@ -87,7 +87,7 @@ func (s *SSServer) startPort(portNum int) error {
 	port := &ssPort{tcpListener: listener, packetConn: packetConn, cipherList: service.NewCipherList()}
 	authFunc := service.NewShadowsocksStreamAuthenticator(port.cipherList, &s.replayCache, s.m)
 	// TODO: Register initial data metrics at zero.
-	tcpHandler := service.NewTCPHandler(portNum, authFunc, s.m, tcpReadTimeout)
+	tcpHandler := service.NewTCPHandler(listener.Addr().String(), authFunc, s.m, tcpReadTimeout)
 	packetHandler := service.NewPacketHandler(s.natTimeout, port.cipherList, s.m)
 	s.ports[portNum] = port
 	go service.StreamServe(service.WrapStreamListener(listener.AcceptTCP), tcpHandler.Handle)
diff --git a/cmd/outline-ss-server/metrics.go b/cmd/outline-ss-server/metrics.go
index 531c16ba..e95ceeb3 100644
--- a/cmd/outline-ss-server/metrics.go
+++ b/cmd/outline-ss-server/metrics.go
@@ -18,7 +18,6 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
-	"strconv"
 	"sync"
 	"time"
 
@@ -357,8 +356,8 @@ func (m *outlineMetrics) RemoveUDPNatEntry(clientAddr net.Addr, accessKey string
 	}
 }
 
-func (m *outlineMetrics) AddTCPProbe(status, drainResult string, port int, clientProxyBytes int64) {
-	m.tcpProbes.WithLabelValues(strconv.Itoa(port), status, drainResult).Observe(float64(clientProxyBytes))
+func (m *outlineMetrics) AddTCPProbe(status, drainResult string, listenerId string, clientProxyBytes int64) {
+	m.tcpProbes.WithLabelValues(listenerId, status, drainResult).Observe(float64(clientProxyBytes))
 }
 
 func (m *outlineMetrics) AddTCPCipherSearch(accessKeyFound bool, timeToCipher time.Duration) {
diff --git a/cmd/outline-ss-server/metrics_test.go b/cmd/outline-ss-server/metrics_test.go
index 353520e4..80e81817 100644
--- a/cmd/outline-ss-server/metrics_test.go
+++ b/cmd/outline-ss-server/metrics_test.go
@@ -68,7 +68,7 @@ func TestMethodsDontPanic(t *testing.T) {
 	ssMetrics.AddUDPPacketFromTarget(ipInfo, "3", "OK", 10, 20)
 	ssMetrics.AddUDPNatEntry(fakeAddr("127.0.0.1:9"), "key-1")
 	ssMetrics.RemoveUDPNatEntry(fakeAddr("127.0.0.1:9"), "key-1")
-	ssMetrics.AddTCPProbe("ERR_CIPHER", "eof", 443, proxyMetrics.ClientProxy)
+	ssMetrics.AddTCPProbe("ERR_CIPHER", "eof", "127.0.0.1:443", proxyMetrics.ClientProxy)
 	ssMetrics.AddTCPCipherSearch(true, 10*time.Millisecond)
 	ssMetrics.AddUDPCipherSearch(true, 10*time.Millisecond)
 }
@@ -164,11 +164,10 @@ func BenchmarkProbe(b *testing.B) {
 	ssMetrics := newPrometheusOutlineMetrics(nil, prometheus.NewRegistry())
 	status := "ERR_REPLAY"
 	drainResult := "other"
-	port := 12345
 	data := metrics.ProxyMetrics{}
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		ssMetrics.AddTCPProbe(status, drainResult, port, data.ClientProxy)
+		ssMetrics.AddTCPProbe(status, drainResult, "127.0.0.1:12345", data.ClientProxy)
 	}
 }
 
diff --git a/internal/integration_test/integration_test.go b/internal/integration_test/integration_test.go
index 4ca2f120..f98319f4 100644
--- a/internal/integration_test/integration_test.go
+++ b/internal/integration_test/integration_test.go
@@ -133,7 +133,7 @@ func TestTCPEcho(t *testing.T) {
 	const testTimeout = 200 * time.Millisecond
 	testMetrics := &service.NoOpTCPMetrics{}
 	authFunc := service.NewShadowsocksStreamAuthenticator(cipherList, &replayCache, testMetrics)
-	handler := service.NewTCPHandler(proxyListener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, testTimeout)
+	handler := service.NewTCPHandler(proxyListener.Addr().String(), authFunc, testMetrics, testTimeout)
 	handler.SetTargetDialer(&transport.TCPDialer{})
 	done := make(chan struct{})
 	go func() {
@@ -202,7 +202,7 @@ func TestRestrictedAddresses(t *testing.T) {
 	const testTimeout = 200 * time.Millisecond
 	testMetrics := &statusMetrics{}
 	authFunc := service.NewShadowsocksStreamAuthenticator(cipherList, nil, testMetrics)
-	handler := service.NewTCPHandler(proxyListener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, testTimeout)
+	handler := service.NewTCPHandler(proxyListener.Addr().String(), authFunc, testMetrics, testTimeout)
 	done := make(chan struct{})
 	go func() {
 		service.StreamServe(service.WrapStreamListener(proxyListener.AcceptTCP), handler.Handle)
@@ -384,7 +384,7 @@ func BenchmarkTCPThroughput(b *testing.B) {
 	const testTimeout = 200 * time.Millisecond
 	testMetrics := &service.NoOpTCPMetrics{}
 	authFunc := service.NewShadowsocksStreamAuthenticator(cipherList, nil, testMetrics)
-	handler := service.NewTCPHandler(proxyListener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, testTimeout)
+	handler := service.NewTCPHandler(proxyListener.Addr().String(), authFunc, testMetrics, testTimeout)
 	handler.SetTargetDialer(&transport.TCPDialer{})
 	done := make(chan struct{})
 	go func() {
@@ -448,7 +448,7 @@ func BenchmarkTCPMultiplexing(b *testing.B) {
 	const testTimeout = 200 * time.Millisecond
 	testMetrics := &service.NoOpTCPMetrics{}
 	authFunc := service.NewShadowsocksStreamAuthenticator(cipherList, &replayCache, testMetrics)
-	handler := service.NewTCPHandler(proxyListener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, testTimeout)
+	handler := service.NewTCPHandler(proxyListener.Addr().String(), authFunc, testMetrics, testTimeout)
 	handler.SetTargetDialer(&transport.TCPDialer{})
 	done := make(chan struct{})
 	go func() {
diff --git a/service/tcp.go b/service/tcp.go
index 85ab9990..2195480b 100644
--- a/service/tcp.go
+++ b/service/tcp.go
@@ -44,7 +44,7 @@ type TCPMetrics interface {
 	AddOpenTCPConnection(clientInfo ipinfo.IPInfo)
 	AddAuthenticatedTCPConnection(clientAddr net.Addr, accessKey string)
 	AddClosedTCPConnection(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string, status string, data metrics.ProxyMetrics, duration time.Duration)
-	AddTCPProbe(status, drainResult string, port int, clientProxyBytes int64)
+	AddTCPProbe(status, drainResult string, listenerId string, clientProxyBytes int64)
 }
 
 func remoteIP(conn net.Conn) netip.Addr {
@@ -162,7 +162,7 @@ func NewShadowsocksStreamAuthenticator(ciphers CipherList, replayCache *ReplayCa
 }
 
 type tcpHandler struct {
-	port         int
+	listenerId   string
 	m            TCPMetrics
 	readTimeout  time.Duration
 	authenticate StreamAuthenticateFunc
@@ -170,9 +170,9 @@ type tcpHandler struct {
 }
 
 // NewTCPService creates a TCPService
-func NewTCPHandler(port int, authenticate StreamAuthenticateFunc, m TCPMetrics, timeout time.Duration) TCPHandler {
+func NewTCPHandler(listenerId string, authenticate StreamAuthenticateFunc, m TCPMetrics, timeout time.Duration) TCPHandler {
 	return &tcpHandler{
-		port:         port,
+		listenerId:   listenerId,
 		m:            m,
 		readTimeout:  timeout,
 		authenticate: authenticate,
@@ -375,7 +375,7 @@ func (h *tcpHandler) absorbProbe(clientConn io.ReadCloser, status string, proxyM
 	_, drainErr := io.Copy(io.Discard, clientConn) // drain socket
 	drainResult := drainErrToString(drainErr)
 	logger.Debugf("Drain error: %v, drain result: %v", drainErr, drainResult)
-	h.m.AddTCPProbe(status, drainResult, h.port, proxyMetrics.ClientProxy)
+	h.m.AddTCPProbe(status, drainResult, h.listenerId, proxyMetrics.ClientProxy)
 }
 
 func drainErrToString(drainErr error) string {
@@ -404,6 +404,6 @@ func (m *NoOpTCPMetrics) GetIPInfo(net.IP) (ipinfo.IPInfo, error) {
 func (m *NoOpTCPMetrics) AddOpenTCPConnection(clientInfo ipinfo.IPInfo) {}
 func (m *NoOpTCPMetrics) AddAuthenticatedTCPConnection(clientAddr net.Addr, accessKey string) {
 }
-func (m *NoOpTCPMetrics) AddTCPProbe(status, drainResult string, port int, clientProxyBytes int64) {
+func (m *NoOpTCPMetrics) AddTCPProbe(status, drainResult string, listenerId string, clientProxyBytes int64) {
 }
 func (m *NoOpTCPMetrics) AddTCPCipherSearch(accessKeyFound bool, timeToCipher time.Duration) {}
diff --git a/service/tcp_test.go b/service/tcp_test.go
index 1a70ed67..5c3bc9df 100644
--- a/service/tcp_test.go
+++ b/service/tcp_test.go
@@ -239,7 +239,7 @@ func (m *probeTestMetrics) AddOpenTCPConnection(clientInfo ipinfo.IPInfo) {
 func (m *probeTestMetrics) AddAuthenticatedTCPConnection(clientAddr net.Addr, accessKey string) {
 }
 
-func (m *probeTestMetrics) AddTCPProbe(status, drainResult string, port int, clientProxyBytes int64) {
+func (m *probeTestMetrics) AddTCPProbe(status, drainResult string, listenerId string, clientProxyBytes int64) {
 	m.mu.Lock()
 	m.probeData = append(m.probeData, clientProxyBytes)
 	m.probeStatus = append(m.probeStatus, status)
@@ -281,7 +281,7 @@ func TestProbeRandom(t *testing.T) {
 	require.NoError(t, err, "MakeTestCiphers failed: %v", err)
 	testMetrics := &probeTestMetrics{}
 	authFunc := NewShadowsocksStreamAuthenticator(cipherList, nil, testMetrics)
-	handler := NewTCPHandler(listener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, 200*time.Millisecond)
+	handler := NewTCPHandler(listener.Addr().String(), authFunc, testMetrics, 200*time.Millisecond)
 	done := make(chan struct{})
 	go func() {
 		StreamServe(WrapStreamListener(listener.AcceptTCP), handler.Handle)
@@ -358,7 +358,7 @@ func TestProbeClientBytesBasicTruncated(t *testing.T) {
 	cipher := firstCipher(cipherList)
 	testMetrics := &probeTestMetrics{}
 	authFunc := NewShadowsocksStreamAuthenticator(cipherList, nil, testMetrics)
-	handler := NewTCPHandler(listener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, 200*time.Millisecond)
+	handler := NewTCPHandler(listener.Addr().String(), authFunc, testMetrics, 200*time.Millisecond)
 	handler.SetTargetDialer(makeValidatingTCPStreamDialer(allowAll))
 	done := make(chan struct{})
 	go func() {
@@ -393,7 +393,7 @@ func TestProbeClientBytesBasicModified(t *testing.T) {
 	cipher := firstCipher(cipherList)
 	testMetrics := &probeTestMetrics{}
 	authFunc := NewShadowsocksStreamAuthenticator(cipherList, nil, testMetrics)
-	handler := NewTCPHandler(listener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, 200*time.Millisecond)
+	handler := NewTCPHandler(listener.Addr().String(), authFunc, testMetrics, 200*time.Millisecond)
 	handler.SetTargetDialer(makeValidatingTCPStreamDialer(allowAll))
 	done := make(chan struct{})
 	go func() {
@@ -429,7 +429,7 @@ func TestProbeClientBytesCoalescedModified(t *testing.T) {
 	cipher := firstCipher(cipherList)
 	testMetrics := &probeTestMetrics{}
 	authFunc := NewShadowsocksStreamAuthenticator(cipherList, nil, testMetrics)
-	handler := NewTCPHandler(listener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, 200*time.Millisecond)
+	handler := NewTCPHandler(listener.Addr().String(), authFunc, testMetrics, 200*time.Millisecond)
 	handler.SetTargetDialer(makeValidatingTCPStreamDialer(allowAll))
 	done := make(chan struct{})
 	go func() {
@@ -472,7 +472,7 @@ func TestProbeServerBytesModified(t *testing.T) {
 	cipher := firstCipher(cipherList)
 	testMetrics := &probeTestMetrics{}
 	authFunc := NewShadowsocksStreamAuthenticator(cipherList, nil, testMetrics)
-	handler := NewTCPHandler(listener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, 200*time.Millisecond)
+	handler := NewTCPHandler(listener.Addr().String(), authFunc, testMetrics, 200*time.Millisecond)
 	done := make(chan struct{})
 	go func() {
 		StreamServe(WrapStreamListener(listener.AcceptTCP), handler.Handle)
@@ -503,7 +503,7 @@ func TestReplayDefense(t *testing.T) {
 	testMetrics := &probeTestMetrics{}
 	const testTimeout = 200 * time.Millisecond
 	authFunc := NewShadowsocksStreamAuthenticator(cipherList, &replayCache, testMetrics)
-	handler := NewTCPHandler(listener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, testTimeout)
+	handler := NewTCPHandler(listener.Addr().String(), authFunc, testMetrics, testTimeout)
 	snapshot := cipherList.SnapshotForClientIP(netip.Addr{})
 	cipherEntry := snapshot[0].Value.(*CipherEntry)
 	cipher := cipherEntry.CryptoKey
@@ -582,7 +582,7 @@ func TestReverseReplayDefense(t *testing.T) {
 	testMetrics := &probeTestMetrics{}
 	const testTimeout = 200 * time.Millisecond
 	authFunc := NewShadowsocksStreamAuthenticator(cipherList, &replayCache, testMetrics)
-	handler := NewTCPHandler(listener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, testTimeout)
+	handler := NewTCPHandler(listener.Addr().String(), authFunc, testMetrics, testTimeout)
 	snapshot := cipherList.SnapshotForClientIP(netip.Addr{})
 	cipherEntry := snapshot[0].Value.(*CipherEntry)
 	cipher := cipherEntry.CryptoKey
@@ -653,7 +653,7 @@ func probeExpectTimeout(t *testing.T, payloadSize int) {
 	require.NoError(t, err, "MakeTestCiphers failed: %v", err)
 	testMetrics := &probeTestMetrics{}
 	authFunc := NewShadowsocksStreamAuthenticator(cipherList, nil, testMetrics)
-	handler := NewTCPHandler(listener.Addr().(*net.TCPAddr).Port, authFunc, testMetrics, testTimeout)
+	handler := NewTCPHandler(listener.Addr().String(), authFunc, testMetrics, testTimeout)
 
 	done := make(chan struct{})
 	go func() {