diff --git a/build-release.sh b/build-release.sh
index 7d9cf49..13cd663 100755
--- a/build-release.sh
+++ b/build-release.sh
@@ -33,8 +33,15 @@ for os in ${OSES[@]}; do
 	then
 		suffix=".exe"
 	fi
-	env CGO_ENABLED=0 GOOS=$os GOARCH=amd64 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_${os}_amd64${suffix} github.com/xtaci/kcptun/client
-	env CGO_ENABLED=0 GOOS=$os GOARCH=amd64 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_${os}_amd64${suffix} github.com/xtaci/kcptun/server
+
+	if [ "$os" == "linux" ];then
+		env CGO_ENABLED=1 GOOS=$os GOARCH=amd64 go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o client_${os}_amd64${suffix} github.com/xtaci/kcptun/client
+		env CGO_ENABLED=1 GOOS=$os GOARCH=amd64 go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o server_${os}_amd64${suffix} github.com/xtaci/kcptun/server
+	else 
+		env CGO_ENABLED=0 GOOS=$os GOARCH=amd64 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_${os}_amd64${suffix} github.com/xtaci/kcptun/client
+		env CGO_ENABLED=0 GOOS=$os GOARCH=amd64 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_${os}_amd64${suffix} github.com/xtaci/kcptun/server
+	fi
+
 	if $UPX; then upx -9 client_${os}_amd64${suffix} server_${os}_amd64${suffix};fi
 	tar -zcf kcptun-${os}-amd64-$VERSION.tar.gz client_${os}_amd64${suffix} server_${os}_amd64${suffix}
 	$sum kcptun-${os}-amd64-$VERSION.tar.gz
@@ -48,8 +55,15 @@ for os in ${OSES[@]}; do
 	then
 		suffix=".exe"
 	fi
-	env CGO_ENABLED=0 GOOS=$os GOARCH=386 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_${os}_386${suffix} github.com/xtaci/kcptun/client
-	env CGO_ENABLED=0 GOOS=$os GOARCH=386 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_${os}_386${suffix} github.com/xtaci/kcptun/server
+
+	if [ "$os" == "linux" ];then
+		env CGO_ENABLED=1 GOOS=$os GOARCH=386 go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o client_${os}_amd64${suffix} github.com/xtaci/kcptun/client
+		env CGO_ENABLED=1 GOOS=$os GOARCH=386 go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o server_${os}_amd64${suffix} github.com/xtaci/kcptun/server
+	else 
+		env CGO_ENABLED=0 GOOS=$os GOARCH=386 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_${os}_amd64${suffix} github.com/xtaci/kcptun/client
+		env CGO_ENABLED=0 GOOS=$os GOARCH=386 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_${os}_amd64${suffix} github.com/xtaci/kcptun/server
+	fi
+
 	if $UPX; then upx -9 client_${os}_386${suffix} server_${os}_386${suffix};fi
 	tar -zcf kcptun-${os}-386-$VERSION.tar.gz client_${os}_386${suffix} server_${os}_386${suffix}
 	$sum kcptun-${os}-386-$VERSION.tar.gz
@@ -58,25 +72,25 @@ done
 # ARM
 ARMS=(5 6 7)
 for v in ${ARMS[@]}; do
-	env CGO_ENABLED=0 GOOS=linux GOARCH=arm GOARM=$v go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_linux_arm$v  github.com/xtaci/kcptun/client
-	env CGO_ENABLED=0 GOOS=linux GOARCH=arm GOARM=$v go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_linux_arm$v  github.com/xtaci/kcptun/server
+	env CGO_ENABLED=1 GOOS=linux GOARCH=arm GOARM=$v go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o client_linux_arm$v  github.com/xtaci/kcptun/client
+	env CGO_ENABLED=1 GOOS=linux GOARCH=arm GOARM=$v go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o server_linux_arm$v  github.com/xtaci/kcptun/server
 if $UPX; then upx -9 client_linux_arm$v server_linux_arm$v;fi
 tar -zcf kcptun-linux-arm$v-$VERSION.tar.gz client_linux_arm$v server_linux_arm$v
 $sum kcptun-linux-arm$v-$VERSION.tar.gz
 done
 
 # ARM64
-env CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_linux_arm64  github.com/xtaci/kcptun/client
-env CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_linux_arm64  github.com/xtaci/kcptun/server
+env CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o client_linux_arm64  github.com/xtaci/kcptun/client
+env CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o server_linux_arm64  github.com/xtaci/kcptun/server
 if $UPX; then upx -9 client_linux_arm64 server_linux_arm64*;fi
 tar -zcf kcptun-linux-arm64-$VERSION.tar.gz client_linux_arm64 server_linux_arm64
 $sum kcptun-linux-arm64-$VERSION.tar.gz
 
 #MIPS32LE
-env CGO_ENABLED=0 GOOS=linux GOARCH=mipsle GOMIPS=softfloat go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_linux_mipsle github.com/xtaci/kcptun/client
-env CGO_ENABLED=0 GOOS=linux GOARCH=mipsle GOMIPS=softfloat go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_linux_mipsle github.com/xtaci/kcptun/server
-env CGO_ENABLED=0 GOOS=linux GOARCH=mips GOMIPS=softfloat go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_linux_mips github.com/xtaci/kcptun/client
-env CGO_ENABLED=0 GOOS=linux GOARCH=mips GOMIPS=softfloat go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_linux_mips github.com/xtaci/kcptun/server
+env CGO_ENABLED=0 GOOS=linux GOARCH=mipsle GOMIPS=softfloat go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o client_linux_mipsle github.com/xtaci/kcptun/client
+env CGO_ENABLED=0 GOOS=linux GOARCH=mipsle GOMIPS=softfloat go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o server_linux_mipsle github.com/xtaci/kcptun/server
+env CGO_ENABLED=0 GOOS=linux GOARCH=mips GOMIPS=softfloat go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o client_linux_mips github.com/xtaci/kcptun/client
+env CGO_ENABLED=0 GOOS=linux GOARCH=mips GOMIPS=softfloat go build -ldflags "$LDFLAGS_LINUX" -gcflags "$GCFLAGS" -o server_linux_mips github.com/xtaci/kcptun/server
 
 if $UPX; then upx -9 client_linux_mips* server_linux_mips*;fi
 tar -zcf kcptun-linux-mipsle-$VERSION.tar.gz client_linux_mipsle server_linux_mipsle
diff --git a/client/config.go b/client/config.go
index a5d3ed4..5e01ed3 100644
--- a/client/config.go
+++ b/client/config.go
@@ -34,6 +34,7 @@ type Config struct {
 	SnmpLog      string `json:"snmplog"`
 	SnmpPeriod   int    `json:"snmpperiod"`
 	Quiet        bool   `json:"quiet"`
+	TCP          bool   `json:"tcp"`
 }
 
 func parseJSONConfig(config *Config, path string) error {
diff --git a/client/main.go b/client/main.go
index ad3a9a5..b9c0abb 100644
--- a/client/main.go
+++ b/client/main.go
@@ -1,3 +1,5 @@
+// +build !linux,amd64
+
 package main
 
 import (
diff --git a/go.mod b/go.mod
index 6133ab7..d555dde 100644
--- a/go.mod
+++ b/go.mod
@@ -1,7 +1,9 @@
 module github.com/xtaci/kcptun
 
 require (
+	github.com/coreos/go-iptables v0.4.1 // indirect
 	github.com/golang/snappy v0.0.1
+	github.com/google/gopacket v1.1.17 // indirect
 	github.com/klauspost/cpuid v1.2.1 // indirect
 	github.com/klauspost/reedsolomon v1.9.2 // indirect
 	github.com/pkg/errors v0.8.1
@@ -11,6 +13,7 @@ require (
 	github.com/urfave/cli v1.20.0
 	github.com/xtaci/kcp-go v5.4.2+incompatible
 	github.com/xtaci/smux v1.3.3
+	github.com/xtaci/tcpraw v1.1.3
 	golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5
 	golang.org/x/net v0.0.0-20190607181551-461777fb6f67 // indirect
 	golang.org/x/sys v0.0.0-20190610200419-93c9922d18ae // indirect
diff --git a/go.sum b/go.sum
index 6a60fc7..5e96766 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,9 @@
+github.com/coreos/go-iptables v0.4.1 h1:TyEMaK2xD/EcB0385QcvX/OvI2XI7s4SJEI2EhZFfEU=
+github.com/coreos/go-iptables v0.4.1/go.mod h1:/mVI274lEDI2ns62jHCDnCyBF9Iwsmekav8Dbxlm1MU=
 github.com/golang/snappy v0.0.1 h1:Qgr9rKW7uDUkrbSmQeiDsGa8SjGyCOGtuasMWwvp2P4=
 github.com/golang/snappy v0.0.1/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
+github.com/google/gopacket v1.1.17 h1:rMrlX2ZY2UbvT+sdz3+6J+pp2z+msCq9MxTU6ymxbBY=
+github.com/google/gopacket v1.1.17/go.mod h1:UdDNZ1OO62aGYVnPhxT1U6aI7ukYtA/kB8vaU0diBUM=
 github.com/klauspost/cpuid v1.2.0 h1:NMpwD2G9JSFOE1/TJjGSo5zG7Yb2bTe7eq1jH+irmeE=
 github.com/klauspost/cpuid v1.2.0/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
 github.com/klauspost/cpuid v1.2.1 h1:vJi+O/nMdFt0vqm8NZBI6wzALWdA2X+egi0ogNyrC/w=
@@ -91,6 +95,8 @@ github.com/xtaci/smux v1.3.2 h1:8NsGbxBW6oSaeLu5E6V8AmklZm6EhBz7BeCOU3Zdhwc=
 github.com/xtaci/smux v1.3.2/go.mod h1:f+nYm6SpuHMy/SH0zpbvAFHT1QoMcgLOsWcFip5KfPw=
 github.com/xtaci/smux v1.3.3 h1:+vnzZHTLGHrj+LzUZEkKmvu4KkG7fj4jwMPqhawvErg=
 github.com/xtaci/smux v1.3.3/go.mod h1:f+nYm6SpuHMy/SH0zpbvAFHT1QoMcgLOsWcFip5KfPw=
+github.com/xtaci/tcpraw v1.1.3 h1:9kYm8HlXn0G/bNH7Xkm7Ypn/w17vnl/JfDQxBWueUAY=
+github.com/xtaci/tcpraw v1.1.3/go.mod h1:dKyZ2V75s0cZ7cbgJYdxPvms7af0joIeOyx1GgJQbLk=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190320223903-b7391e95e576 h1:aUX/1G2gFSs4AsJJg2cL3HuoRhCSCz733FE5GUSuaT4=
 golang.org/x/crypto v0.0.0-20190320223903-b7391e95e576/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
diff --git a/server/config.go b/server/config.go
index b3c7ea6..5858ccb 100644
--- a/server/config.go
+++ b/server/config.go
@@ -32,6 +32,7 @@ type Config struct {
 	SnmpPeriod   int    `json:"snmpperiod"`
 	Pprof        bool   `json:"pprof"`
 	Quiet        bool   `json:"quiet"`
+	TCP          bool   `json:"tcp"`
 }
 
 func parseJSONConfig(config *Config, path string) error {
diff --git a/server/main.go b/server/main.go
index f68dfff..a3afcd6 100644
--- a/server/main.go
+++ b/server/main.go
@@ -1,3 +1,5 @@
+// +build !linux,amd64
+
 package main
 
 import (