diff --git a/README.md b/README.md
index 4c63ba1..16f17e7 100644
--- a/README.md
+++ b/README.md
@@ -142,6 +142,8 @@ glider 0.15.0 usage:
     	source ip or source interface
   -listen value
     	listen url, format: SCHEME://[USER|METHOD:PASSWORD@][HOST]:PORT?PARAMS
+  -logflags int
+    	log flags, do not change it if you do not know what it is, ref: https://pkg.go.dev/log#pkg-constants (default 19)
   -maxfailures int
     	max failures to change forwarder status to disabled (default 3)
   -relaytimeout int
diff --git a/config.go b/config.go
index aa08fe3..7d1a330 100644
--- a/config.go
+++ b/config.go
@@ -16,7 +16,8 @@ var flag = conflag.New()
 
 // Config is global config struct.
 type Config struct {
-	Verbose bool
+	Verbose  bool
+	LogFlags int
 
 	Listens []string
 
@@ -40,6 +41,7 @@ func parseConfig() *Config {
 	flag.SetOutput(os.Stdout)
 
 	flag.BoolVar(&conf.Verbose, "verbose", false, "verbose mode")
+	flag.IntVar(&conf.LogFlags, "logflags", 19, "log flags, do not change it if you do not know what it is, ref: https://pkg.go.dev/log#pkg-constants")
 	flag.StringSliceUniqVar(&conf.Listens, "listen", nil, "listen url, format: SCHEME://[USER|METHOD:PASSWORD@][HOST]:PORT?PARAMS")
 
 	flag.StringSliceUniqVar(&conf.Forwards, "forward", nil, "forward url, format: SCHEME://[USER|METHOD:PASSWORD@][HOST]:PORT?PARAMS[,SCHEME://[USER|METHOD:PASSWORD@][HOST]:PORT?PARAMS]")
@@ -81,6 +83,7 @@ func parseConfig() *Config {
 
 	// setup a log func
 	if conf.Verbose {
+		log.SetFlag(conf.LogFlags)
 		log.F = log.Debugf
 	}
 
diff --git a/log/log.go b/log/log.go
index 7b45f49..8e7d3a6 100644
--- a/log/log.go
+++ b/log/log.go
@@ -8,8 +8,9 @@ import (
 // F is the main log function.
 var F = func(string, ...interface{}) {}
 
-func init() {
-	stdlog.SetFlags(stdlog.Flags() | stdlog.Lshortfile)
+// SetFlag sets the output flags for the logger.
+func SetFlag(flag int) {
+	stdlog.SetFlags(flag)
 }
 
 // Debugf prints debug log.
diff --git a/proxy/tproxy/tproxy_linux.go b/proxy/tproxy/tproxy_linux.go
index 3af95d7..8bf8773 100644
--- a/proxy/tproxy/tproxy_linux.go
+++ b/proxy/tproxy/tproxy_linux.go
@@ -73,6 +73,8 @@ func (s *TProxy) ListenAndServeUDP() {
 		return
 	}
 
+	log.F("[tproxyu] listening UDP on %s", s.addr)
+
 	var nm sync.Map
 	buf := make([]byte, proxy.UDPBufSize)