diff --git a/cmd/outline-ss-server/metrics.go b/cmd/outline-ss-server/metrics.go
index ed737083..e576420e 100644
--- a/cmd/outline-ss-server/metrics.go
+++ b/cmd/outline-ss-server/metrics.go
@@ -333,7 +333,7 @@ func (m *outlineMetrics) AddUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net
 	m.tunnelTimeTracker.startConnection(clientInfo, clientAddr, accessKey)
 }
 
-func (m *outlineMetrics) RemoveUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string) {
+func (m *outlineMetrics) RemoveUDPNatEntry(clientAddr net.Addr, accessKey string) {
 	m.udpRemovedNatEntries.Inc()
 
 	m.tunnelTimeTracker.stopConnection(clientAddr, accessKey)
diff --git a/cmd/outline-ss-server/metrics_test.go b/cmd/outline-ss-server/metrics_test.go
index 44c37b5e..065a906c 100644
--- a/cmd/outline-ss-server/metrics_test.go
+++ b/cmd/outline-ss-server/metrics_test.go
@@ -62,7 +62,7 @@ func TestMethodsDontPanic(t *testing.T) {
 	ssMetrics.AddUDPPacketFromClient(ipInfo, "2", "OK", 10, 20)
 	ssMetrics.AddUDPPacketFromTarget(ipInfo, "3", "OK", 10, 20)
 	ssMetrics.AddUDPNatEntry(ipInfo, fakeAddr("127.0.0.1:9"), "key-1")
-	ssMetrics.RemoveUDPNatEntry(ipInfo, 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.AddTCPCipherSearch(true, 10*time.Millisecond)
 	ssMetrics.AddUDPCipherSearch(true, 10*time.Millisecond)
@@ -231,6 +231,6 @@ func BenchmarkNAT(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		ssMetrics.AddUDPNatEntry(ipinfo, fakeAddr("127.0.0.1:9"), "key-0")
-		ssMetrics.RemoveUDPNatEntry(ipinfo, fakeAddr("127.0.0.1:9"), "key-0")
+		ssMetrics.RemoveUDPNatEntry(fakeAddr("127.0.0.1:9"), "key-0")
 	}
 }
diff --git a/internal/integration_test/integration_test.go b/internal/integration_test/integration_test.go
index cc563e32..40433680 100644
--- a/internal/integration_test/integration_test.go
+++ b/internal/integration_test/integration_test.go
@@ -270,7 +270,7 @@ func (m *fakeUDPMetrics) AddUDPPacketFromTarget(clientInfo ipinfo.IPInfo, access
 func (m *fakeUDPMetrics) AddUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string) {
 	m.natAdded++
 }
-func (m *fakeUDPMetrics) RemoveUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string) {
+func (m *fakeUDPMetrics) RemoveUDPNatEntry(clientAddr net.Addr, accessKey string) {
 	// Not tested because it requires waiting for a long timeout.
 }
 func (m *fakeUDPMetrics) AddUDPCipherSearch(accessKeyFound bool, timeToCipher time.Duration) {}
diff --git a/service/udp.go b/service/udp.go
index 2706d26a..1c3a0221 100644
--- a/service/udp.go
+++ b/service/udp.go
@@ -37,7 +37,7 @@ type UDPMetrics interface {
 	AddUDPPacketFromClient(clientInfo ipinfo.IPInfo, accessKey, status string, clientProxyBytes, proxyTargetBytes int)
 	AddUDPPacketFromTarget(clientInfo ipinfo.IPInfo, accessKey, status string, targetProxyBytes, proxyClientBytes int)
 	AddUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string)
-	RemoveUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string)
+	RemoveUDPNatEntry(clientAddr net.Addr, accessKey string)
 
 	// Shadowsocks metrics
 	AddUDPCipherSearch(accessKeyFound bool, timeToCipher time.Duration)
@@ -361,7 +361,7 @@ func (m *natmap) Add(clientAddr net.Addr, clientConn net.PacketConn, cryptoKey *
 	m.running.Add(1)
 	go func() {
 		timedCopy(clientAddr, clientConn, entry, keyID, m.metrics)
-		m.metrics.RemoveUDPNatEntry(clientInfo, clientAddr, keyID)
+		m.metrics.RemoveUDPNatEntry(clientAddr, keyID)
 		if pc := m.del(clientAddr.String()); pc != nil {
 			pc.Close()
 		}
@@ -477,6 +477,6 @@ func (m *NoOpUDPMetrics) AddUDPPacketFromTarget(clientInfo ipinfo.IPInfo, access
 }
 func (m *NoOpUDPMetrics) AddUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string) {
 }
-func (m *NoOpUDPMetrics) RemoveUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string) {
+func (m *NoOpUDPMetrics) RemoveUDPNatEntry(clientAddr net.Addr, accessKey string) {
 }
 func (m *NoOpUDPMetrics) AddUDPCipherSearch(accessKeyFound bool, timeToCipher time.Duration) {}
diff --git a/service/udp_test.go b/service/udp_test.go
index 9c5c9130..6066f8f6 100644
--- a/service/udp_test.go
+++ b/service/udp_test.go
@@ -116,7 +116,7 @@ func (m *natTestMetrics) AddUDPPacketFromTarget(clientInfo ipinfo.IPInfo, access
 func (m *natTestMetrics) AddUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string) {
 	m.natEntriesAdded++
 }
-func (m *natTestMetrics) RemoveUDPNatEntry(clientInfo ipinfo.IPInfo, clientAddr net.Addr, accessKey string) {
+func (m *natTestMetrics) RemoveUDPNatEntry(clientAddr net.Addr, accessKey string) {
 }
 func (m *natTestMetrics) AddUDPCipherSearch(accessKeyFound bool, timeToCipher time.Duration) {}