diff --git a/gost.go b/gost.go
index 90c47f3..328955d 100644
--- a/gost.go
+++ b/gost.go
@@ -13,6 +13,7 @@ import (
 	"strconv"
 	"strings"
 	//"sync/atomic"
+	//"fmt"
 	"time"
 )
 
@@ -56,56 +57,193 @@ func (g *Gost) handle(conn net.Conn) {
 		g.cli(conn)
 		return
 	}
-
 	// as server
 	g.srv(conn)
 }
 
 func (g *Gost) cli(conn net.Conn) {
+	lg := NewLog()
+
 	sconn, err := g.connect(g.Saddr)
 	if err != nil {
+		lg.Logln(err)
 		return
 	}
 	defer sconn.Close()
 
+	laddr := sconn.(*net.TCPConn).LocalAddr().String()
+	lg.Logln(laddr)
+
+	if _, err := sconn.Write([]byte{5, 1, 0}); err != nil {
+		lg.Logln(err)
+		return
+	}
+	lg.Logln(">>>|", []byte{5, 1, 0})
+
+	b := make([]byte, 8192)
+
+	n, err := io.ReadFull(sconn, b[:2])
+	if err != nil {
+		lg.Logln(err)
+		return
+	}
+	lg.Logln("<<<|", b[:n])
+
+	n, err = conn.Read(b)
+	if err != nil {
+		lg.Logln(err)
+		return
+	}
+
+	if b[0] == 5 { // socks5,NO AUTHENTICATION
+		lg.Logln("|>>>", b[:n])
+
+		if _, err := conn.Write([]byte{5, 0}); err != nil {
+			lg.Logln(err)
+			return
+		}
+		lg.Logln("|<<<", []byte{5, 0})
+
+		cmd, err := ReadCmd(conn)
+		if err != nil {
+			lg.Logln(err)
+			return
+		}
+		lg.Logln("|>>>", cmd)
+
+		if err = cmd.Write(sconn); err != nil {
+			lg.Logln(err)
+			return
+		}
+		lg.Logln(">>>|", cmd)
+
+		cmd, err = ReadCmd(sconn)
+		if err != nil {
+			lg.Logln(err)
+			return
+		}
+		lg.Logln("<<<|", cmd)
+
+		if err = cmd.Write(conn); err != nil {
+			lg.Logln(err)
+			return
+		}
+		lg.Logln("|<<<", cmd)
+
+		lg.Logln()
+		lg.Flush()
+
+		g.transport(conn, sconn)
+		return
+	}
+
+	//log.Println(string(b[:n]))
+	req, err := http.ReadRequest(bufio.NewReader(bytes.NewReader(b[:n])))
+	if err != nil {
+		lg.Logln(err)
+		return
+	}
+	lg.Logln(req.Method, req.RequestURI)
+
+	var addr string
+	var port uint16
+
+	host := strings.Split(req.Host, ":")
+	if len(host) == 1 {
+		addr = host[0]
+		port = 80
+	}
+	if len(host) == 2 {
+		addr = host[0]
+		n, _ := strconv.ParseUint(host[1], 10, 16)
+		port = uint16(n)
+	}
+
+	cmd := NewCmd(CmdConnect, AddrDomain, addr, port)
+	if err = cmd.Write(sconn); err != nil {
+		lg.Logln(err)
+		return
+	}
+	lg.Logln(">>>|", cmd)
+
+	if cmd, err = ReadCmd(sconn); err != nil {
+		lg.Logln(err)
+		return
+	}
+	lg.Logln("<<<|", cmd)
+
+	if cmd.Cmd != Succeeded {
+		conn.Write([]byte("HTTP/1.1 503 Service unavailable\r\n" +
+			"Proxy-Agent: gost/1.0\r\n\r\n"))
+		return
+	}
+
+	if req.Method == "CONNECT" {
+		if _, err = conn.Write(
+			[]byte("HTTP/1.1 200 Connection established\r\n" +
+				"Proxy-Agent: gost/2.0\r\n\r\n")); err != nil {
+			lg.Logln(err)
+			return
+		}
+	} else {
+		if err = req.Write(sconn); err != nil {
+			lg.Logln(err)
+			return
+		}
+	}
+
+	lg.Logln()
+	lg.Flush()
 	g.transport(conn, sconn)
-	return
 }
 
 func (g *Gost) srv(conn net.Conn) {
 	b := make([]byte, 8192)
+	lg := NewLog()
 
 	n, err := conn.Read(b)
 	if err != nil {
-		log.Println(err)
+		lg.Logln(err)
 		return
 	}
 
-	if bytes.Equal(b[:n], []byte{5, 1, 0}) { // socks5,NO AUTHENTICATION
-		log.Println("read cmd:", b[:n])
+	if b[0] == 5 { // socks5,NO AUTHENTICATION
+		lg.Logln("|>>>", b[:n])
 		if _, err := conn.Write([]byte{5, 0}); err != nil {
-			log.Println(err)
+			lg.Logln(err)
 			return
 		}
+		lg.Logln("|<<<", []byte{5, 0})
 
 		cmd, err := ReadCmd(conn)
 		if err != nil {
+			lg.Logln(err)
 			return
 		}
+		lg.Logln("|>>>", cmd)
+
 		host := cmd.Addr + ":" + strconv.Itoa(int(cmd.Port))
-		log.Println("connect", host)
+		lg.Logln("connect", host)
+
 		tconn, err := g.connect(host)
 		if err != nil {
-			log.Println(err)
-			NewCmd(ConnRefused, 0, "", 0).Write(conn)
+			lg.Logln(err)
+			cmd = NewCmd(ConnRefused, 0, "", 0)
+			cmd.Write(conn)
+			lg.Logln("|<<<", cmd)
 			return
 		}
 		defer tconn.Close()
 
-		if err = NewCmd(Succeeded, AddrIPv4, "0.0.0.0", 0).Write(conn); err != nil {
-			log.Println(err)
+		cmd = NewCmd(Succeeded, AddrIPv4, "0.0.0.0", 0)
+		if err = cmd.Write(conn); err != nil {
+			lg.Logln(err)
 			return
 		}
+		lg.Logln("|<<<", cmd)
+
+		lg.Logln()
+		lg.Flush()
 
 		g.transport(conn, tconn)
 		return
@@ -114,18 +252,18 @@ func (g *Gost) srv(conn net.Conn) {
 	//log.Println(string(b[:n]))
 	req, err := http.ReadRequest(bufio.NewReader(bytes.NewReader(b[:n])))
 	if err != nil {
-		log.Println(err)
+		lg.Logln(err)
 		return
 	}
 
-	log.Println(req.Method, req.RequestURI)
+	lg.Logln(req.Method, req.RequestURI)
 	host := req.Host
 	if !strings.Contains(host, ":") {
 		host = host + ":80"
 	}
 	tconn, err := g.connect(host)
 	if err != nil {
-		log.Println(err)
+		lg.Logln(err)
 		conn.Write([]byte("HTTP/1.1 503 Service unavailable\r\n" +
 			"Proxy-Agent: gost/1.0\r\n\r\n"))
 		return
@@ -136,14 +274,19 @@ func (g *Gost) srv(conn net.Conn) {
 		if _, err = conn.Write(
 			[]byte("HTTP/1.1 200 Connection established\r\n" +
 				"Proxy-Agent: gost/1.0\r\n\r\n")); err != nil {
+			lg.Logln(err)
 			return
 		}
 	} else {
 		if err := req.Write(tconn); err != nil {
+			lg.Logln(err)
 			return
 		}
 	}
 
+	lg.Logln()
+	lg.Flush()
+
 	g.transport(conn, tconn)
 }
 
@@ -151,6 +294,7 @@ func (g *Gost) connect(addr string) (net.Conn, error) {
 	if len(g.Proxy) == 0 {
 		taddr, err := net.ResolveTCPAddr("tcp", addr)
 		if err != nil {
+			log.Println(err)
 			return nil, err
 		}
 		return net.DialTCP("tcp", nil, taddr)
diff --git a/log.go b/log.go
new file mode 100644
index 0000000..ec727b5
--- /dev/null
+++ b/log.go
@@ -0,0 +1,50 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+)
+
+type BufferedLog struct {
+	buffer *bytes.Buffer
+	w      io.WriteCloser
+}
+
+func NewLog() *BufferedLog {
+	return &BufferedLog{
+		buffer: &bytes.Buffer{},
+		w:      os.Stdout,
+	}
+}
+
+func NewFileLog(file *os.File) *BufferedLog {
+	return &BufferedLog{
+		buffer: &bytes.Buffer{},
+		w:      file,
+	}
+}
+
+func (log *BufferedLog) Log(a ...interface{}) (int, error) {
+	return fmt.Fprint(log.buffer, a...)
+}
+
+func (log *BufferedLog) Logln(a ...interface{}) (int, error) {
+	return fmt.Fprintln(log.buffer, a...)
+}
+
+func (log *BufferedLog) Logf(format string, a ...interface{}) (int, error) {
+	return fmt.Fprintf(log.buffer, format, a...)
+}
+
+func (log *BufferedLog) Flush() error {
+	defer func() {
+		if log.w != os.Stdout {
+			log.w.Close()
+		}
+	}()
+
+	_, err := log.buffer.WriteTo(log.w)
+	return err
+}
diff --git a/socks5.go b/socks5.go
index c8795b3..892eb5b 100644
--- a/socks5.go
+++ b/socks5.go
@@ -3,8 +3,9 @@ package main
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"io"
-	"log"
+	//"log"
 	"net"
 )
 
@@ -92,7 +93,6 @@ func ReadCmd(r io.Reader) (*Cmd, error) {
 	if err != nil {
 		return nil, err
 	}
-	log.Println("read cmd:", b[:n])
 	if n < 10 {
 		return nil, ErrBadFormat
 	}
@@ -159,12 +159,12 @@ func (cmd *Cmd) Write(w io.Writer) (err error) {
 	binary.BigEndian.PutUint16(b[pos:], cmd.Port)
 	pos += 2
 
-	log.Println("write cmd:", b[:pos])
 	_, err = w.Write(b[:pos])
 
 	return
 }
 
-func (cmd *Cmd) GetError() error {
-	return cmdErrMap[cmd.Cmd]
+func (cmd *Cmd) String() string {
+	return fmt.Sprintf("5 %d 0 %d %s %d",
+		cmd.Cmd, cmd.AddrType, cmd.Addr, cmd.Port)
 }