diff --git a/cmd/shadowsocks-local/local.go b/cmd/shadowsocks-local/local.go
index 604bf9f7..256c8280 100644
--- a/cmd/shadowsocks-local/local.go
+++ b/cmd/shadowsocks-local/local.go
@@ -34,6 +34,8 @@ var (
 const (
 	socksVer5       = 5
 	socksCmdConnect = 1
+
+	defaultTimeout = 300
 )
 
 func init() {
@@ -414,7 +416,7 @@ func main() {
 	flag.StringVar(&cmdConfig.LocalAddress, "b", "", "local address, listen only to this address if specified")
 	flag.StringVar(&cmdConfig.Password, "k", "", "password")
 	flag.IntVar(&cmdConfig.ServerPort, "p", 0, "server port")
-	flag.IntVar(&cmdConfig.Timeout, "t", 300, "timeout in seconds")
+	flag.IntVar(&cmdConfig.Timeout, "t", 0, "timeout in seconds")
 	flag.IntVar(&cmdConfig.LocalPort, "l", 0, "local socks5 proxy port")
 	flag.StringVar(&cmdConfig.Method, "m", "", "encryption method, default: aes-256-cfb")
 	flag.BoolVar((*bool)(&debug), "d", false, "print debug message")
@@ -461,6 +463,12 @@ func main() {
 	if config.Method == "" {
 		config.Method = "aes-256-cfb"
 	}
+	if config.Timeout == 0 {
+		// must use ss.UpdateConfig to modify readTimeout in ss package
+		ss.UpdateConfig(config, &ss.Config{
+			Timeout: defaultTimeout,
+		})
+	}
 	if len(config.ServerPassword) == 0 {
 		if !enoughOptions(config) {
 			fmt.Fprintln(os.Stderr, "must specify server address, password and both server/local port")
diff --git a/cmd/shadowsocks-server/server.go b/cmd/shadowsocks-server/server.go
index 28099981..6507e598 100644
--- a/cmd/shadowsocks-server/server.go
+++ b/cmd/shadowsocks-server/server.go
@@ -36,6 +36,8 @@ const (
 	lenIPv6   = net.IPv6len + 2 // ipv6 + 2port
 	lenDmBase = 2               // 1addrLen + 2port, plus addrLen
 	// lenHmacSha1 = 10
+
+	defaultTimeout = 300
 )
 
 var debug ss.DebugLog
@@ -437,7 +439,7 @@ func main() {
 	flag.StringVar(&configFile, "c", "config.json", "specify config file")
 	flag.StringVar(&cmdConfig.Password, "k", "", "password")
 	flag.IntVar(&cmdConfig.ServerPort, "p", 0, "server port")
-	flag.IntVar(&cmdConfig.Timeout, "t", 300, "timeout in seconds")
+	flag.IntVar(&cmdConfig.Timeout, "t", 0, "timeout in seconds")
 	flag.StringVar(&cmdConfig.Method, "m", "", "encryption method, default: aes-256-cfb")
 	flag.IntVar(&core, "core", 0, "maximum number of CPU cores to use, default is determinied by Go runtime")
 	flag.BoolVar((*bool)(&debug), "d", false, "print debug message")
@@ -468,6 +470,12 @@ func main() {
 	if config.Method == "" {
 		config.Method = "aes-256-cfb"
 	}
+	if config.Timeout == 0 {
+		// must use ss.UpdateConfig to modify readTimeout in ss package
+		ss.UpdateConfig(config, &ss.Config{
+			Timeout: defaultTimeout,
+		})
+	}
 	if err = ss.CheckCipherMethod(config.Method); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)