diff --git a/pkg/components/handler/http/handler.go b/pkg/components/handler/http/handler.go
index 181fb0a..94912fe 100644
--- a/pkg/components/handler/http/handler.go
+++ b/pkg/components/handler/http/handler.go
@@ -3,10 +3,17 @@ package http
 import (
 	"bufio"
 	"context"
+	"encoding/base64"
+	"encoding/binary"
+	"errors"
+	"hash/crc32"
 	"net"
 	"net/http"
 	"net/http/httputil"
+	"os"
+	"strconv"
 	"strings"
+	"time"
 
 	"github.com/go-gost/gost/pkg/auth"
 	"github.com/go-gost/gost/pkg/chain"
@@ -43,9 +50,9 @@ func (h *Handler) Init(md md.Metadata) error {
 }
 
 func (h *Handler) parseMetadata(md md.Metadata) error {
-	h.md.proxyAgent = md.GetString(proxyAgent)
+	h.md.proxyAgent = md.GetString(proxyAgentKey)
 
-	if v, _ := md.Get(auths).([]interface{}); len(v) > 0 {
+	if v, _ := md.Get(authsKey).([]interface{}); len(v) > 0 {
 		authenticator := auth.NewLocalAuthenticator(nil)
 		for _, auth := range v {
 			if s, _ := auth.(string); s != "" {
@@ -59,6 +66,17 @@ func (h *Handler) parseMetadata(md md.Metadata) error {
 		}
 		h.md.authenticator = authenticator
 	}
+
+	if v := md.GetString(probeResistKey); v != "" {
+		if ss := strings.SplitN(v, ":", 2); len(ss) == 2 {
+			h.md.probeResist = &probeResist{
+				Type:  ss[0],
+				Value: ss[1],
+				Knock: md.GetString(knockKey),
+			}
+		}
+	}
+
 	return nil
 }
 
@@ -66,8 +84,8 @@ func (h *Handler) Handle(ctx context.Context, conn net.Conn) {
 	defer conn.Close()
 
 	h.logger = h.logger.WithFields(map[string]interface{}{
-		"src":   conn.RemoteAddr(),
-		"local": conn.LocalAddr(),
+		"src":   conn.RemoteAddr().String(),
+		"local": conn.LocalAddr().String(),
 	})
 
 	req, err := http.ReadRequest(bufio.NewReader(conn))
@@ -85,43 +103,32 @@ func (h *Handler) handleRequest(ctx context.Context, conn net.Conn, req *http.Re
 		return
 	}
 
-	/*
-		// try to get the actual host.
-		if v := req.Header.Get("Gost-Target"); v != "" {
-			if h, err := decodeServerName(v); err == nil {
-				req.Host = h
-			}
+	// try to get the actual host.
+	if v := req.Header.Get("Gost-Target"); v != "" {
+		if h, err := h.decodeServerName(v); err == nil {
+			req.Host = h
 		}
-	*/
+	}
+	req.Header.Del("Gost-Target")
 
 	host := req.Host
 	if _, port, _ := net.SplitHostPort(host); port == "" {
 		host = net.JoinHostPort(host, "80")
 	}
 
-	h.logger = h.logger.WithFields(map[string]interface{}{
+	fields := map[string]interface{}{
 		"dst": host,
-	})
+	}
+	if u, _, _ := h.basicProxyAuth(req.Header.Get("Proxy-Authorization")); u != "" {
+		fields["user"] = u
+	}
+	h.logger = h.logger.WithFields(fields)
 
 	if h.logger.IsLevelEnabled(logger.DebugLevel) {
 		dump, _ := httputil.DumpRequest(req, false)
 		h.logger.Debug(string(dump))
 	}
-	/*
-		u, _, _ := basicProxyAuth(req.Header.Get("Proxy-Authorization"))
-		if u != "" {
-			u += "@"
-		}
-		log.Logf("[http] %s%s -> %s -> %s",
-			u, conn.RemoteAddr(), h.options.Node.String(), host)
 
-		if Debug {
-			dump, _ := httputil.DumpRequest(req, false)
-			log.Logf("[http] %s -> %s\n%s", conn.RemoteAddr(), conn.LocalAddr(), string(dump))
-		}
-
-		req.Header.Del("Gost-Target")
-	*/
 	resp := &http.Response{
 		ProtoMajor: 1,
 		ProtoMinor: 1,
@@ -164,24 +171,20 @@ func (h *Handler) handleRequest(ctx context.Context, conn net.Conn, req *http.Re
 		}
 	*/
 
-	/*
-		if !h.authenticate(conn, req, resp) {
-			return
-		}
-	*/
+	if !h.authenticate(conn, req, resp) {
+		return
+	}
 
 	if req.Method == "PRI" ||
 		(req.Method != http.MethodConnect && req.URL.Scheme != "http") {
 		resp.StatusCode = http.StatusBadRequest
-		/*
-			if Debug {
-				dump, _ := httputil.DumpResponse(resp, false)
-				log.Logf("[http] %s <- %s\n%s",
-					conn.RemoteAddr(), conn.LocalAddr(), string(dump))
-			}
-		*/
-
 		resp.Write(conn)
+
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			dump, _ := httputil.DumpResponse(resp, false)
+			h.logger.Debug(string(dump))
+		}
+
 		return
 	}
 
@@ -190,14 +193,12 @@ func (h *Handler) handleRequest(ctx context.Context, conn net.Conn, req *http.Re
 	cc, err := h.dial(ctx, host)
 	if err != nil {
 		resp.StatusCode = http.StatusServiceUnavailable
-
-		/*
-			if Debug {
-				dump, _ := httputil.DumpResponse(resp, false)
-				log.Logf("[http] %s <- %s\n%s", conn.RemoteAddr(), conn.LocalAddr(), string(dump))
-			}
-		*/
 		resp.Write(conn)
+
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			dump, _ := httputil.DumpResponse(resp, false)
+			h.logger.Debug(string(dump))
+		}
 		return
 	}
 	defer cc.Close()
@@ -205,11 +206,19 @@ func (h *Handler) handleRequest(ctx context.Context, conn net.Conn, req *http.Re
 	if req.Method == http.MethodConnect {
 		resp.StatusCode = http.StatusOK
 		resp.Status = "200 Connection established"
-		resp.Write(conn)
+
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			dump, _ := httputil.DumpResponse(resp, false)
+			h.logger.Debug(string(dump))
+		}
+		if err = resp.Write(conn); err != nil {
+			h.logger.Warn(err)
+			return
+		}
 	} else {
 		req.Header.Del("Proxy-Connection")
-
 		if err = req.Write(cc); err != nil {
+			h.logger.Warn(err)
 			return
 		}
 	}
@@ -252,9 +261,123 @@ func (h *Handler) dial(ctx context.Context, addr string) (conn net.Conn, err err
 
 		conn, err = route.Dial(ctx, "tcp", addr)
 		if err != nil {
+			h.logger.Warn("retry:", err)
 			continue
 		}
 	}
 
 	return
 }
+
+func (h *Handler) decodeServerName(s string) (string, error) {
+	b, err := base64.RawURLEncoding.DecodeString(s)
+	if err != nil {
+		return "", err
+	}
+	if len(b) < 4 {
+		return "", errors.New("invalid name")
+	}
+	v, err := base64.RawURLEncoding.DecodeString(string(b[4:]))
+	if err != nil {
+		return "", err
+	}
+	if crc32.ChecksumIEEE(v) != binary.BigEndian.Uint32(b[:4]) {
+		return "", errors.New("invalid name")
+	}
+	return string(v), nil
+}
+
+func (h *Handler) basicProxyAuth(proxyAuth string) (username, password string, ok bool) {
+	if proxyAuth == "" {
+		return
+	}
+
+	if !strings.HasPrefix(proxyAuth, "Basic ") {
+		return
+	}
+	c, err := base64.StdEncoding.DecodeString(strings.TrimPrefix(proxyAuth, "Basic "))
+	if err != nil {
+		return
+	}
+	cs := string(c)
+	s := strings.IndexByte(cs, ':')
+	if s < 0 {
+		return
+	}
+
+	return cs[:s], cs[s+1:], true
+}
+
+func (h *Handler) authenticate(conn net.Conn, req *http.Request, resp *http.Response) (ok bool) {
+	u, p, _ := h.basicProxyAuth(req.Header.Get("Proxy-Authorization"))
+	if h.md.authenticator == nil || h.md.authenticator.Authenticate(u, p) {
+		return true
+	}
+
+	pr := h.md.probeResist
+	// probing resistance is enabled, and knocking host is mismatch.
+	if pr != nil && (pr.Knock == "" || !strings.EqualFold(req.URL.Hostname(), pr.Knock)) {
+		resp.StatusCode = http.StatusServiceUnavailable // default status code
+
+		switch pr.Type {
+		case "code":
+			resp.StatusCode, _ = strconv.Atoi(pr.Value)
+		case "web":
+			url := pr.Value
+			if !strings.HasPrefix(url, "http") {
+				url = "http://" + url
+			}
+			if r, err := http.Get(url); err == nil {
+				resp = r
+				defer r.Body.Close()
+			}
+		case "host":
+			cc, err := net.Dial("tcp", pr.Value)
+			if err == nil {
+				defer cc.Close()
+
+				req.Write(cc)
+				handler.Transport(conn, cc)
+				return
+			}
+		case "file":
+			f, _ := os.Open(pr.Value)
+			if f != nil {
+				resp.StatusCode = http.StatusOK
+				if finfo, _ := f.Stat(); finfo != nil {
+					resp.ContentLength = finfo.Size()
+				}
+				resp.Header.Set("Content-Type", "text/html")
+				resp.Body = f
+			}
+		}
+	}
+
+	if resp.StatusCode == 0 {
+		resp.StatusCode = http.StatusProxyAuthRequired
+		resp.Header.Add("Proxy-Authenticate", "Basic realm=\"gost\"")
+		if strings.ToLower(req.Header.Get("Proxy-Connection")) == "keep-alive" {
+			// XXX libcurl will keep sending auth request in same conn
+			// which we don't supported yet.
+			resp.Header.Add("Connection", "close")
+			resp.Header.Add("Proxy-Connection", "close")
+		}
+
+		h.logger.Info("proxy authentication required")
+	} else {
+		resp.Header = http.Header{}
+		resp.Header.Set("Server", "nginx/1.20.1")
+		resp.Header.Set("Date", time.Now().Format(http.TimeFormat))
+		if resp.StatusCode == http.StatusOK {
+			resp.Header.Set("Connection", "keep-alive")
+		}
+	}
+
+	if h.logger.IsLevelEnabled(logger.DebugLevel) {
+		dump, _ := httputil.DumpResponse(resp, false)
+		h.logger.Debug(string(dump))
+	}
+
+	resp.Write(conn)
+	return
+}
diff --git a/pkg/components/handler/http/metadata.go b/pkg/components/handler/http/metadata.go
index e4086fb..92e8ada 100644
--- a/pkg/components/handler/http/metadata.go
+++ b/pkg/components/handler/http/metadata.go
@@ -3,9 +3,11 @@ package http
 import "github.com/go-gost/gost/pkg/auth"
 
 const (
-	addr       = "addr"
-	proxyAgent = "proxyAgent"
-	auths      = "auths"
+	addrKey        = "addr"
+	proxyAgentKey  = "proxyAgent"
+	authsKey       = "auths"
+	probeResistKey = "probeResist"
+	knockKey       = "knock"
 )
 
 type metadata struct {
@@ -13,4 +15,11 @@ type metadata struct {
 	authenticator auth.Authenticator
 	proxyAgent    string
 	retryCount    int
+	probeResist   *probeResist
+}
+
+type probeResist struct {
+	Type  string
+	Value string
+	Knock string
 }