diff --git a/chain.go b/chain.go
index 9a409d9..ca7d15b 100644
--- a/chain.go
+++ b/chain.go
@@ -1,9 +1,10 @@
 package gost
 
 import (
+	"bytes"
 	"errors"
+	"fmt"
 	"net"
-	"strings"
 
 	"github.com/go-log/log"
 )
@@ -15,6 +16,8 @@ var (
 
 // Chain is a proxy chain that holds a list of proxy nodes.
 type Chain struct {
+	isRoute    bool
+	Retries    int
 	nodeGroups []*NodeGroup
 }
 
@@ -27,6 +30,12 @@ func NewChain(nodes ...Node) *Chain {
 	return chain
 }
 
+func newRoute(nodes ...Node) *Chain {
+	chain := NewChain(nodes...)
+	chain.isRoute = true
+	return chain
+}
+
 // Nodes returns the proxy nodes that the chain holds.
 // If a node is a node group, the first node in the group will be returned.
 func (c *Chain) Nodes() (nodes []Node) {
@@ -50,8 +59,8 @@ func (c *Chain) LastNode() Node {
 	if c.IsEmpty() {
 		return Node{}
 	}
-	last := c.nodeGroups[len(c.nodeGroups)-1]
-	return last.nodes[0]
+	group := c.nodeGroups[len(c.nodeGroups)-1]
+	return group.nodes[0].Clone()
 }
 
 // LastNodeGroup returns the last group of the group list.
@@ -90,17 +99,27 @@ func (c *Chain) IsEmpty() bool {
 
 // Dial connects to the target address addr through the chain.
 // If the chain is empty, it will use the net.Dial directly.
-func (c *Chain) Dial(addr string) (net.Conn, error) {
+func (c *Chain) Dial(addr string) (conn net.Conn, err error) {
 	if c.IsEmpty() {
-		return net.Dial("tcp", addr)
+		return net.DialTimeout("tcp", addr, DialTimeout)
 	}
 
+	for i := 0; i < c.Retries+1; i++ {
+		conn, err = c.dial(addr)
+		if err == nil {
+			break
+		}
+	}
+	return
+}
+
+func (c *Chain) dial(addr string) (net.Conn, error) {
 	route, err := c.selectRoute()
 	if err != nil {
 		return nil, err
 	}
 
-	conn, err := c.getConn(route)
+	conn, err := route.getConn()
 	if err != nil {
 		return nil, err
 	}
@@ -116,77 +135,60 @@ func (c *Chain) Dial(addr string) (net.Conn, error) {
 // Conn obtains a handshaked connection to the last node of the chain.
 // If the chain is empty, it returns an ErrEmptyChain error.
 func (c *Chain) Conn() (conn net.Conn, err error) {
-	route, err := c.selectRoute()
-	if err != nil {
-		return nil, err
-	}
-	conn, err = c.getConn(route)
-	return
-}
-
-func (c *Chain) selectRoute() (route *Chain, err error) {
-	route = NewChain()
-	for _, group := range c.nodeGroups {
-		selector := group.Selector
-		if selector == nil {
-			selector = &defaultSelector{}
-		}
-		// select node from node group
-		node, err := selector.Select(group.Nodes(), group.Options...)
+	for i := 0; i < c.Retries+1; i++ {
+		var route *Chain
+		route, err = c.selectRoute()
 		if err != nil {
-			return nil, err
+			continue
 		}
-		if node.Client.Transporter.Multiplex() {
-			node.DialOptions = append(node.DialOptions,
-				ChainDialOption(route),
-			)
-			route = NewChain() // cutoff the chain for multiplex
+		conn, err = route.getConn()
+		if err != nil {
+			continue
 		}
-		route.AddNode(node)
+
+		break
 	}
 	return
 }
 
-func (c *Chain) getConn(route *Chain) (conn net.Conn, err error) {
-	if route.IsEmpty() {
+func (c *Chain) getConn() (conn net.Conn, err error) {
+	if c.IsEmpty() {
 		err = ErrEmptyChain
 		return
 	}
-	nodes := route.Nodes()
+	nodes := c.Nodes()
 	node := nodes[0]
 
-	addr, err := selectIP(&node)
-	if err != nil {
-		return
-	}
-	cn, err := node.Client.Dial(addr, node.DialOptions...)
+	cn, err := node.Client.Dial(node.Addr, node.DialOptions...)
 	if err != nil {
+		node.MarkDead()
 		return
 	}
 
 	cn, err = node.Client.Handshake(cn, node.HandshakeOptions...)
 	if err != nil {
+		node.MarkDead()
 		return
 	}
+	node.ResetDead()
 
 	preNode := node
 	for _, node := range nodes[1:] {
-		addr, err = selectIP(&node)
-		if err != nil {
-			return
-		}
-
 		var cc net.Conn
-		cc, err = preNode.Client.Connect(cn, addr)
+		cc, err = preNode.Client.Connect(cn, node.Addr)
 		if err != nil {
 			cn.Close()
+			node.MarkDead()
 			return
 		}
 		cc, err = node.Client.Handshake(cc, node.HandshakeOptions...)
 		if err != nil {
 			cn.Close()
+			node.MarkDead()
 			return
 		}
+		node.ResetDead()
+
 		cn = cc
 		preNode = node
 	}
@@ -195,29 +197,34 @@ func (c *Chain) getConn(route *Chain) (conn net.Conn, err error) {
 	return
 }
 
-func selectIP(node *Node) (string, error) {
-	addr := node.Addr
-	s := node.IPSelector
-	if s == nil {
-		s = &RandomIPSelector{}
+func (c *Chain) selectRoute() (route *Chain, err error) {
+	if c.isRoute {
+		return c, nil
 	}
-	// select IP from IP list
-	ip, err := s.Select(node.IPs)
-	if err != nil {
-		return "", err
-	}
-	if ip != "" {
-		if !strings.Contains(ip, ":") {
-			_, sport, err := net.SplitHostPort(addr)
-			if err != nil {
-				return "", err
-			}
-			ip = ip + ":" + sport
+
+	buf := bytes.Buffer{}
+	route = newRoute()
+	route.Retries = c.Retries
+
+	for _, group := range c.nodeGroups {
+		node, err := group.Next()
+		if err != nil {
+			return nil, err
 		}
-		addr = ip
-		// override the original address
-		node.HandshakeOptions = append(node.HandshakeOptions, AddrHandshakeOption(addr))
+		buf.WriteString(fmt.Sprintf("%s -> ", node.String()))
+
+		if node.Client.Transporter.Multiplex() {
+			node.DialOptions = append(node.DialOptions,
+				ChainDialOption(route),
+			)
+			route = newRoute() // cutoff the chain for multiplex.
+			route.Retries = c.Retries
+		}
+
+		route.AddNode(node)
 	}
-	log.Log("select IP:", node.Addr, node.IPs, addr)
-	return addr, nil
+	if Debug {
+		log.Log("select route:", buf.String())
+	}
+	return
 }
diff --git a/client.go b/client.go
index e4a05f9..8a74998 100644
--- a/client.go
+++ b/client.go
@@ -116,6 +116,7 @@ func ChainDialOption(chain *Chain) DialOption {
 // HandshakeOptions describes the options for handshake.
 type HandshakeOptions struct {
 	Addr       string
+	Host       string
 	User       *url.Userinfo
 	Timeout    time.Duration
 	Interval   time.Duration
@@ -136,6 +137,13 @@ func AddrHandshakeOption(addr string) HandshakeOption {
 	}
 }
 
+// HostHandshakeOption specifies the hostname
+func HostHandshakeOption(host string) HandshakeOption {
+	return func(opts *HandshakeOptions) {
+		opts.Host = host
+	}
+}
+
 // UserHandshakeOption specifies the user used by Transporter.Handshake
 func UserHandshakeOption(user *url.Userinfo) HandshakeOption {
 	return func(opts *HandshakeOptions) {
diff --git a/cmd/gost/gost.json b/cmd/gost/gost.json
index 8602a51..e7217c9 100644
--- a/cmd/gost/gost.json
+++ b/cmd/gost/gost.json
@@ -1,4 +1,6 @@
 {
+    "Debug": false,
+    "Retries": 1,
     "ServeNodes": [
         ":8080",
         "ss://chacha20:12345678@:8338"
@@ -6,5 +8,23 @@
     "ChainNodes": [
         "http://192.168.1.1:8080",
         "https://10.0.2.1:443"
+    ],
+
+    "Routes": [
+        {
+            "Retries": 1,
+            "ServeNodes": [
+                "ws://:1443"
+            ],
+            "ChainNodes": [
+                "socks://:192.168.1.1:1080"
+            ]
+        },
+        {
+            "Retries": 3,
+            "ServeNodes": [
+                "quic://:443"
+            ]
+        }
     ]
 }
\ No newline at end of file
diff --git a/cmd/gost/main.go b/cmd/gost/main.go
index 5ebbe66..14071cb 100644
--- a/cmd/gost/main.go
+++ b/cmd/gost/main.go
@@ -22,10 +22,8 @@ import (
 )
 
 var (
-	options struct {
-		ChainNodes, ServeNodes stringList
-		Debug                  bool
-	}
+	options route
+	routes  []route
 )
 
 func init() {
@@ -43,12 +41,17 @@ func init() {
 	flag.BoolVar(&printVersion, "V", false, "print version")
 	flag.Parse()
 
+	if len(options.ServeNodes) > 0 {
+		routes = append(routes, options)
+	}
+	gost.Debug = options.Debug
+
 	if err := loadConfigureFile(configureFile); err != nil {
 		log.Log(err)
 		os.Exit(1)
 	}
 
-	if flag.NFlag() == 0 {
+	if flag.NFlag() == 0 || len(routes) == 0 {
 		flag.PrintDefaults()
 		os.Exit(0)
 	}
@@ -57,8 +60,6 @@ func init() {
 		fmt.Fprintf(os.Stderr, "gost %s (%s)\n", gost.Version, runtime.Version())
 		os.Exit(0)
 	}
-
-	gost.Debug = options.Debug
 }
 
 func main() {
@@ -72,45 +73,73 @@ func main() {
 		Certificates: []tls.Certificate{cert},
 	}
 
-	chain, err := initChain()
-	if err != nil {
-		log.Log(err)
-		os.Exit(1)
-	}
-	if err := serve(chain); err != nil {
-		log.Log(err)
-		os.Exit(1)
+	for _, route := range routes {
+		if err := route.serve(); err != nil {
+			log.Log(err)
+			os.Exit(1)
+		}
 	}
 
 	select {}
 }
 
-func initChain() (*gost.Chain, error) {
+type route struct {
+	ChainNodes, ServeNodes stringList
+	Retries                int
+	Debug                  bool
+}
+
+func (r *route) initChain() (*gost.Chain, error) {
 	chain := gost.NewChain()
-	for _, ns := range options.ChainNodes {
+	chain.Retries = r.Retries
+
+	gid := 1 // group ID
+
+	for _, ns := range r.ChainNodes {
+		ngroup := gost.NewNodeGroup()
+		ngroup.ID = gid
+		gid++
+
 		// parse the base node
-		node, err := parseChainNode(ns)
+		nodes, err := parseChainNode(ns)
 		if err != nil {
 			return nil, err
 		}
 
-		ngroup := gost.NewNodeGroup(node)
+		nid := 1 // node ID
 
-		// parse node peers if exists
-		peerCfg, err := loadPeerConfig(node.Values.Get("peer"))
+		for i := range nodes {
+			nodes[i].ID = nid
+			nid++
+		}
+		ngroup.AddNode(nodes...)
+
+		// parse peer nodes if exists
+		peerCfg, err := loadPeerConfig(nodes[0].Values.Get("peer"))
 		if err != nil {
 			log.Log(err)
 		}
+		peerCfg.Validate()
 		ngroup.Options = append(ngroup.Options,
-			// gost.WithFilter(),
+			gost.WithFilter(&gost.FailFilter{
+				MaxFails:    peerCfg.MaxFails,
+				FailTimeout: time.Duration(peerCfg.FailTimeout) * time.Second,
+			}),
 			gost.WithStrategy(parseStrategy(peerCfg.Strategy)),
 		)
+
 		for _, s := range peerCfg.Nodes {
-			node, err = parseChainNode(s)
+			nodes, err = parseChainNode(s)
 			if err != nil {
 				return nil, err
 			}
-			ngroup.AddNode(node)
+
+			for i := range nodes {
+				nodes[i].ID = nid
+				nid++
+			}
+
+			ngroup.AddNode(nodes...)
 		}
 
 		chain.AddNodeGroup(ngroup)
@@ -119,15 +148,12 @@ func initChain() (*gost.Chain, error) {
 	return chain, nil
 }
 
-func parseChainNode(ns string) (node gost.Node, err error) {
-	node, err = gost.ParseNode(ns)
+func parseChainNode(ns string) (nodes []gost.Node, err error) {
+	node, err := gost.ParseNode(ns)
 	if err != nil {
 		return
 	}
 
-	node.IPs = parseIP(node.Values.Get("ip"))
-	node.IPSelector = &gost.RoundRobinIPSelector{}
-
 	users, err := parseUsers(node.Values.Get("secrets"))
 	if err != nil {
 		return
@@ -135,7 +161,7 @@ func parseChainNode(ns string) (node gost.Node, err error) {
 	if node.User == nil && len(users) > 0 {
 		node.User = users[0]
 	}
-	serverName, _, _ := net.SplitHostPort(node.Addr)
+	serverName, sport, _ := net.SplitHostPort(node.Addr)
 	if serverName == "" {
 		serverName = "localhost" // default server name
 	}
@@ -177,7 +203,7 @@ func parseChainNode(ns string) (node gost.Node, err error) {
 		*/
 		config, err := parseKCPConfig(node.Values.Get("c"))
 		if err != nil {
-			return node, err
+			return nil, err
 		}
 		tr = gost.KCPTransporter(config)
 	case "ssh":
@@ -206,7 +232,7 @@ func parseChainNode(ns string) (node gost.Node, err error) {
 
 	case "obfs4":
 		if err := gost.Obfs4Init(node, false); err != nil {
-			return node, err
+			return nil, err
 		}
 		tr = gost.Obfs4Transporter()
 	case "ohttp":
@@ -249,24 +275,41 @@ func parseChainNode(ns string) (node gost.Node, err error) {
 
 	interval, _ := strconv.Atoi(node.Values.Get("ping"))
 	retry, _ := strconv.Atoi(node.Values.Get("retry"))
-	node.HandshakeOptions = append(node.HandshakeOptions,
+	handshakeOptions := []gost.HandshakeOption{
 		gost.AddrHandshakeOption(node.Addr),
+		gost.HostHandshakeOption(node.Host),
 		gost.UserHandshakeOption(node.User),
 		gost.TLSConfigHandshakeOption(tlsCfg),
-		gost.IntervalHandshakeOption(time.Duration(interval)*time.Second),
-		gost.TimeoutHandshakeOption(time.Duration(timeout)*time.Second),
+		gost.IntervalHandshakeOption(time.Duration(interval) * time.Second),
+		gost.TimeoutHandshakeOption(time.Duration(timeout) * time.Second),
 		gost.RetryHandshakeOption(retry),
-	)
+	}
 	node.Client = &gost.Client{
 		Connector:   connector,
 		Transporter: tr,
 	}
 
+	ips := parseIP(node.Values.Get("ip"), sport)
+	for _, ip := range ips {
+		node.Addr = ip
+		node.HandshakeOptions = append(handshakeOptions, gost.AddrHandshakeOption(ip))
+		nodes = append(nodes, node)
+	}
+	if len(ips) == 0 {
+		node.HandshakeOptions = handshakeOptions
+		nodes = []gost.Node{node}
+	}
+
 	return
 }
 
-func serve(chain *gost.Chain) error {
-	for _, ns := range options.ServeNodes {
+func (r *route) serve() error {
+	chain, err := r.initChain()
+	if err != nil {
+		return err
+	}
+
+	for _, ns := range r.ServeNodes {
 		node, err := gost.ParseNode(ns)
 		if err != nil {
 			return err
@@ -475,9 +518,24 @@ func loadConfigureFile(configureFile string) error {
 	if err != nil {
 		return err
 	}
-	if err := json.Unmarshal(content, &options); err != nil {
+	var cfg struct {
+		route
+		Routes []route
+	}
+	if err := json.Unmarshal(content, &cfg); err != nil {
 		return err
 	}
+
+	if len(cfg.route.ServeNodes) > 0 {
+		routes = append(routes, cfg.route)
+	}
+	for _, route := range cfg.Routes {
+		if len(cfg.route.ServeNodes) > 0 {
+			routes = append(routes, route)
+		}
+	}
+	gost.Debug = cfg.Debug
+
 	return nil
 }
 
@@ -544,16 +602,23 @@ func parseUsers(authFile string) (users []*url.Userinfo, err error) {
 	return
 }
 
-func parseIP(s string) (ips []string) {
+func parseIP(s string, port string) (ips []string) {
 	if s == "" {
-		return nil
+		return
 	}
+	if port == "" {
+		port = "8080" // default port
+	}
+
 	file, err := os.Open(s)
 	if err != nil {
 		ss := strings.Split(s, ",")
 		for _, s := range ss {
 			s = strings.TrimSpace(s)
 			if s != "" {
+				if !strings.Contains(s, ":") {
+					s = s + ":" + port
+				}
 				ips = append(ips, s)
 			}
 
@@ -567,15 +632,20 @@ func parseIP(s string) (ips []string) {
 		if line == "" || strings.HasPrefix(line, "#") {
 			continue
 		}
+		if !strings.Contains(line, ":") {
+			line = line + ":" + port
+		}
 		ips = append(ips, line)
 	}
 	return
 }
 
 type peerConfig struct {
-	Strategy string   `json:"strategy"`
-	Filters  []string `json:"filters"`
-	Nodes    []string `json:"nodes"`
+	Strategy    string   `json:"strategy"`
+	Filters     []string `json:"filters"`
+	MaxFails    int      `json:"max_fails"`
+	FailTimeout int      `json:"fail_timeout"`
+	Nodes       []string `json:"nodes"`
 }
 
 func loadPeerConfig(peer string) (config peerConfig, err error) {
@@ -590,13 +660,23 @@ func loadPeerConfig(peer string) (config peerConfig, err error) {
 	return
 }
 
-func parseStrategy(s string) gost.Strategy {
-	switch s {
-	case "round":
-		return &gost.RoundStrategy{}
-	case "random":
-		fallthrough
-	default:
-		return &gost.RandomStrategy{}
+func (cfg *peerConfig) Validate() {
+	if cfg.MaxFails <= 0 {
+		cfg.MaxFails = 3
+	}
+	if cfg.FailTimeout <= 0 {
+		cfg.FailTimeout = 30 // seconds
+	}
+}
+
+func parseStrategy(s string) gost.Strategy {
+	switch s {
+	case "random":
+		return &gost.RandomStrategy{}
+	case "round":
+		fallthrough
+	default:
+		return &gost.RoundStrategy{}
+
 	}
 }
diff --git a/cmd/gost/peer.json b/cmd/gost/peer.json
new file mode 100644
index 0000000..a4eee76
--- /dev/null
+++ b/cmd/gost/peer.json
@@ -0,0 +1,10 @@
+{
+    "strategy": "round",
+    "max_fails": 3,
+    "fail_timeout": 30,
+    "nodes":[
+        "socks5://:1081",
+        "socks://:1082",
+        "socks4a://:1083"
+    ]
+}
\ No newline at end of file
diff --git a/gost.go b/gost.go
index 39b818f..2a8baeb 100644
--- a/gost.go
+++ b/gost.go
@@ -56,6 +56,7 @@ func SetLogger(logger log.Logger) {
 	log.DefaultLogger = logger
 }
 
+// GenCertificate generates a random TLS certificate
 func GenCertificate() (cert tls.Certificate, err error) {
 	rawCert, rawKey, err := generateKeyPair()
 	if err != nil {
diff --git a/handler.go b/handler.go
index 2b51e4e..84162b3 100644
--- a/handler.go
+++ b/handler.go
@@ -95,7 +95,8 @@ func (h *autoHandler) Handle(conn net.Conn) {
 	cc := &bufferdConn{Conn: conn, br: br}
 	switch b[0] {
 	case gosocks4.Ver4:
-		return // SOCKS4(a) does not suppport authentication method, so we ignore it.
+		cc.Close()
+		return // SOCKS4(a) does not suppport authentication method, so we ignore it for security reason.
 	case gosocks5.Ver5:
 		SOCKS5Handler(h.options...).Handle(cc)
 	default: // http
diff --git a/http.go b/http.go
index 0612f50..b88942d 100644
--- a/http.go
+++ b/http.go
@@ -93,6 +93,13 @@ func (h *httpHandler) Handle(conn net.Conn) {
 		return
 	}
 
+	h.handleRequest(conn, req)
+}
+
+func (h *httpHandler) handleRequest(conn net.Conn, req *http.Request) {
+	if req == nil {
+		return
+	}
 	if Debug {
 		dump, _ := httputil.DumpRequest(req, false)
 		log.Logf("[http] %s -> %s\n%s", conn.RemoteAddr(), req.Host, string(dump))
diff --git a/node.go b/node.go
index 4a2ef1a..14d5b17 100644
--- a/node.go
+++ b/node.go
@@ -1,14 +1,18 @@
 package gost
 
 import (
+	"fmt"
 	"net/url"
 	"strings"
+	"sync/atomic"
+	"time"
 )
 
 // Node is a proxy node, mainly used to construct a proxy chain.
 type Node struct {
+	ID               int
 	Addr             string
-	IPs              []string
+	Host             string
 	Protocol         string
 	Transport        string
 	Remote           string // remote address, used by tcp/udp port forwarding
@@ -17,7 +21,9 @@ type Node struct {
 	DialOptions      []DialOption
 	HandshakeOptions []HandshakeOption
 	Client           *Client
-	IPSelector       IPSelector
+	group            *NodeGroup
+	failCount        uint32
+	failTime         int64
 }
 
 // ParseNode parses the node info.
@@ -38,6 +44,7 @@ func ParseNode(s string) (node Node, err error) {
 
 	node = Node{
 		Addr:   u.Host,
+		Host:   u.Host,
 		Remote: strings.Trim(u.EscapedPath(), "/"),
 		Values: u.Query(),
 		User:   u.User,
@@ -79,8 +86,68 @@ func ParseNode(s string) (node Node, err error) {
 	return
 }
 
+// MarkDead marks the node fail status.
+func (node *Node) MarkDead() {
+	atomic.AddUint32(&node.failCount, 1)
+	atomic.StoreInt64(&node.failTime, time.Now().Unix())
+
+	if node.group == nil {
+		return
+	}
+	for i := range node.group.nodes {
+		if node.group.nodes[i].ID == node.ID {
+			atomic.AddUint32(&node.group.nodes[i].failCount, 1)
+			atomic.StoreInt64(&node.group.nodes[i].failTime, time.Now().Unix())
+			break
+		}
+	}
+}
+
+// ResetDead resets the node fail status.
+func (node *Node) ResetDead() {
+	atomic.StoreUint32(&node.failCount, 0)
+	atomic.StoreInt64(&node.failTime, 0)
+
+	if node.group == nil {
+		return
+	}
+
+	for i := range node.group.nodes {
+		if node.group.nodes[i].ID == node.ID {
+			atomic.StoreUint32(&node.group.nodes[i].failCount, 0)
+			atomic.StoreInt64(&node.group.nodes[i].failTime, 0)
+			break
+		}
+	}
+}
+
+// Clone clones the node, it will prevent data race.
+func (node *Node) Clone() Node {
+	return Node{
+		ID:               node.ID,
+		Addr:             node.Addr,
+		Host:             node.Host,
+		Protocol:         node.Protocol,
+		Transport:        node.Transport,
+		Remote:           node.Remote,
+		User:             node.User,
+		Values:           node.Values,
+		DialOptions:      node.DialOptions,
+		HandshakeOptions: node.HandshakeOptions,
+		Client:           node.Client,
+		group:            node.group,
+		failCount:        atomic.LoadUint32(&node.failCount),
+		failTime:         atomic.LoadInt64(&node.failTime),
+	}
+}
+
+func (node *Node) String() string {
+	return fmt.Sprintf("%d@%s", node.ID, node.Addr)
+}
+
 // NodeGroup is a group of nodes.
 type NodeGroup struct {
+	ID       int
 	nodes    []Node
 	Options  []SelectOption
 	Selector NodeSelector
@@ -94,17 +161,34 @@ func NewNodeGroup(nodes ...Node) *NodeGroup {
 }
 
 // AddNode adds node or node list into group
-func (ng *NodeGroup) AddNode(node ...Node) {
-	if ng == nil {
+func (group *NodeGroup) AddNode(node ...Node) {
+	if group == nil {
 		return
 	}
-	ng.nodes = append(ng.nodes, node...)
+	group.nodes = append(group.nodes, node...)
 }
 
 // Nodes returns node list in the group
-func (ng *NodeGroup) Nodes() []Node {
-	if ng == nil {
+func (group *NodeGroup) Nodes() []Node {
+	if group == nil {
 		return nil
 	}
-	return ng.nodes
+	return group.nodes
+}
+
+// Next selects the next node from group.
+// It also selects IP if the IP list exists.
+func (group *NodeGroup) Next() (node Node, err error) {
+	selector := group.Selector
+	if selector == nil {
+		selector = &defaultSelector{}
+	}
+	// select node from node group
+	node, err = selector.Select(group.Nodes(), group.Options...)
+	if err != nil {
+		return
+	}
+	node.group = group
+
+	return
 }
diff --git a/obfs.go b/obfs.go
index 424ed58..2c7da09 100644
--- a/obfs.go
+++ b/obfs.go
@@ -35,7 +35,7 @@ func (tr *obfsHTTPTransporter) Handshake(conn net.Conn, options ...HandshakeOpti
 	for _, option := range options {
 		option(opts)
 	}
-	return &obfsHTTPConn{Conn: conn}, nil
+	return &obfsHTTPConn{Conn: conn, host: opts.Host}, nil
 }
 
 type obfsHTTPListener struct {
@@ -66,6 +66,7 @@ func (l *obfsHTTPListener) Accept() (net.Conn, error) {
 
 type obfsHTTPConn struct {
 	net.Conn
+	host           string
 	request        *http.Request
 	response       *http.Response
 	rbuf           []byte
@@ -151,7 +152,7 @@ func (c *obfsHTTPConn) clientHandshake() (err error) {
 			Method:     http.MethodGet,
 			ProtoMajor: 1,
 			ProtoMinor: 1,
-			URL:        &url.URL{Scheme: "http", Host: "www.baidu.com"},
+			URL:        &url.URL{Scheme: "http", Host: c.host},
 			Header:     make(http.Header),
 		}
 		r.Header.Set("Connection", "keep-alive")
diff --git a/selector.go b/selector.go
index 675a254..bea2c65 100644
--- a/selector.go
+++ b/selector.go
@@ -2,6 +2,8 @@ package gost
 
 import (
 	"errors"
+	"math/rand"
+	"sync"
 	"sync/atomic"
 	"time"
 )
@@ -37,52 +39,6 @@ func (s *defaultSelector) Select(nodes []Node, opts ...SelectOption) (Node, erro
 	return sopts.Strategy.Apply(nodes), nil
 }
 
-// Filter is used to filter a node during the selection process
-type Filter interface {
-	Filter([]Node) []Node
-}
-
-// Strategy is a selection strategy e.g random, round robin
-type Strategy interface {
-	Apply([]Node) Node
-	String() string
-}
-
-// RoundStrategy is a strategy for node selector
-type RoundStrategy struct {
-	count uint64
-}
-
-// Apply applies the round robin strategy for the nodes
-func (s *RoundStrategy) Apply(nodes []Node) Node {
-	if len(nodes) == 0 {
-		return Node{}
-	}
-	old := s.count
-	atomic.AddUint64(&s.count, 1)
-	return nodes[int(old%uint64(len(nodes)))]
-}
-
-func (s *RoundStrategy) String() string {
-	return "round"
-}
-
-// RandomStrategy is a strategy for node selector
-type RandomStrategy struct{}
-
-// Apply applies the random strategy for the nodes
-func (s *RandomStrategy) Apply(nodes []Node) Node {
-	if len(nodes) == 0 {
-		return Node{}
-	}
-
-	return nodes[time.Now().Nanosecond()%len(nodes)]
-}
-
-func (s *RandomStrategy) String() string {
-	return "random"
-}
-
 // SelectOption used when making a select call
 type SelectOption func(*SelectOptions)
 
@@ -107,43 +63,86 @@ func WithStrategy(s Strategy) SelectOption {
 	}
 }
 
-// IPSelector as a mechanism to pick IPs and mark their status.
-type IPSelector interface {
-	Select(ips []string) (string, error)
+// Strategy is a selection strategy e.g random, round robin
+type Strategy interface {
+	Apply([]Node) Node
 	String() string
 }
 
-// RandomIPSelector is an IP Selector that selects an IP with random strategy.
-type RandomIPSelector struct {
-}
-
-// Select selects an IP from ips list.
-func (s *RandomIPSelector) Select(ips []string) (string, error) {
-	if len(ips) == 0 {
-		return "", nil
-	}
-	return ips[time.Now().Nanosecond()%len(ips)], nil
-}
-
-func (s *RandomIPSelector) String() string {
-	return "random"
-}
-
-// RoundRobinIPSelector is an IP Selector that selects an IP with round-robin strategy.
-type RoundRobinIPSelector struct {
+// RoundStrategy is a strategy for node selector
+type RoundStrategy struct {
 	count uint64
 }
 
-// Select selects an IP from ips list.
-func (s *RoundRobinIPSelector) Select(ips []string) (string, error) {
-	if len(ips) == 0 {
-		return "", nil
+// Apply applies the round robin strategy for the nodes
+func (s *RoundStrategy) Apply(nodes []Node) Node {
+	if len(nodes) == 0 {
+		return Node{}
 	}
-	old := s.count
+	old := atomic.LoadUint64(&s.count)
 	atomic.AddUint64(&s.count, 1)
-	return ips[int(old%uint64(len(ips)))], nil
+	return nodes[int(old%uint64(len(nodes)))]
 }
 
-func (s *RoundRobinIPSelector) String() string {
+func (s *RoundStrategy) String() string {
 	return "round"
 }
+
+// RandomStrategy is a strategy for node selector
+type RandomStrategy struct {
+	Seed int64
+	rand *rand.Rand
+	once sync.Once
+}
+
+// Apply applies the random strategy for the nodes
+func (s *RandomStrategy) Apply(nodes []Node) Node {
+	s.once.Do(func() {
+		seed := s.Seed
+		if seed == 0 {
+			seed = time.Now().UnixNano()
+		}
+		s.rand = rand.New(rand.NewSource(seed))
+	})
+	if len(nodes) == 0 {
+		return Node{}
+	}
+
+	return nodes[s.rand.Int()%len(nodes)]
+}
+
+func (s *RandomStrategy) String() string {
+	return "random"
+}
+
+// Filter is used to filter a node during the selection process
+type Filter interface {
+	Filter([]Node) []Node
+	String() string
+}
+
+// FailFilter filters the dead node.
+// A node is marked as dead if its failed count is greater than MaxFails.
+type FailFilter struct {
+	MaxFails    int
+	FailTimeout time.Duration
+}
+
+// Filter filters nodes.
+func (f *FailFilter) Filter(nodes []Node) []Node {
+	if f.MaxFails <= 0 {
+		return nodes
+	}
+	nl := []Node{}
+	for i := range nodes {
+		if atomic.LoadUint32(&nodes[i].failCount) < uint32(f.MaxFails) ||
+			time.Since(time.Unix(atomic.LoadInt64(&nodes[i].failTime), 0)) >= f.FailTimeout {
+			nl = append(nl, nodes[i].Clone())
+		}
+	}
+	return nl
+}
+
+func (f *FailFilter) String() string {
+	return "fail"
+}
diff --git a/sni.go b/sni.go
index d4ec608..2cb9800 100644
--- a/sni.go
+++ b/sni.go
@@ -11,6 +11,7 @@ import (
 	"hash/crc32"
 	"io"
 	"net"
+	"net/http"
 	"strings"
 	"sync"
 
@@ -53,15 +54,22 @@ func (h *sniHandler) Handle(conn net.Conn) {
 		return
 	}
 	conn = &bufferdConn{br: br, Conn: conn}
+	defer conn.Close()
 
 	if hdr[0] != dissector.Handshake {
-		// We assume that it is HTTP request
-		HTTPHandler(h.options...).Handle(conn)
+		// We assume it is an HTTP request
+		req, err := http.ReadRequest(bufio.NewReader(conn))
+		if !req.URL.IsAbs() {
+			req.URL.Scheme = "http" // make sure that the URL is absolute
+		}
+		if err != nil {
+			log.Logf("[sni] %s - %s : %s", conn.RemoteAddr(), conn.LocalAddr(), err)
+			return
+		}
+		HTTPHandler(h.options...).(*httpHandler).handleRequest(conn, req)
 		return
 	}
 
-	defer conn.Close()
-
 	b, host, err := readClientHelloRecord(conn, "", false)
 	if err != nil {
 		log.Log("[sni]", err)
diff --git a/ss.go b/ss.go
index 3cc702d..e180cb6 100644
--- a/ss.go
+++ b/ss.go
@@ -124,11 +124,15 @@ func (h *shadowHandler) Handle(conn net.Conn) {
 
 	log.Logf("[ss] %s - %s", conn.RemoteAddr(), conn.LocalAddr())
 
+	conn.SetReadDeadline(time.Now().Add(ReadTimeout))
 	addr, err := h.getRequest(conn)
 	if err != nil {
 		log.Logf("[ss] %s - %s : %s", conn.RemoteAddr(), conn.LocalAddr(), err)
 		return
 	}
+	// clear timer
+	conn.SetReadDeadline(time.Time{})
+
 	log.Logf("[ss] %s -> %s", conn.RemoteAddr(), addr)
 
 	if !Can("tcp", addr, h.options.Whitelist, h.options.Blacklist) {
@@ -165,19 +169,16 @@ const (
 )
 
 // This function is copied from shadowsocks library with some modification.
-func (h *shadowHandler) getRequest(conn net.Conn) (host string, err error) {
+func (h *shadowHandler) getRequest(r io.Reader) (host string, err error) {
 	// buf size should at least have the same size with the largest possible
 	// request size (when addrType is 3, domain name has at most 256 bytes)
 	// 1(addrType) + 1(lenByte) + 256(max length address) + 2(port)
 	buf := make([]byte, smallBufferSize)
 
 	// read till we get possible domain length field
-	conn.SetReadDeadline(time.Now().Add(ReadTimeout))
-	if _, err = io.ReadFull(conn, buf[:idType+1]); err != nil {
+	if _, err = io.ReadFull(r, buf[:idType+1]); err != nil {
 		return
 	}
-	// clear timer
-	conn.SetReadDeadline(time.Time{})
 
 	var reqStart, reqEnd int
 	addrType := buf[idType]
@@ -187,16 +188,16 @@ func (h *shadowHandler) getRequest(conn net.Conn) (host string, err error) {
 	case typeIPv6:
 		reqStart, reqEnd = idIP0, idIP0+lenIPv6
 	case typeDm:
-		if _, err = io.ReadFull(conn, buf[idType+1:idDmLen+1]); err != nil {
+		if _, err = io.ReadFull(r, buf[idType+1:idDmLen+1]); err != nil {
 			return
 		}
-		reqStart, reqEnd = idDm0, int(idDm0+buf[idDmLen]+lenDmBase)
+		reqStart, reqEnd = idDm0, idDm0+int(buf[idDmLen])+lenDmBase
 	default:
 		err = fmt.Errorf("addr type %d not supported", addrType&ss.AddrMask)
 		return
 	}
 
-	if _, err = io.ReadFull(conn, buf[reqStart:reqEnd]); err != nil {
+	if _, err = io.ReadFull(r, buf[reqStart:reqEnd]); err != nil {
 		return
 	}
 
@@ -209,7 +210,7 @@ func (h *shadowHandler) getRequest(conn net.Conn) (host string, err error) {
 	case typeIPv6:
 		host = net.IP(buf[idIP0 : idIP0+net.IPv6len]).String()
 	case typeDm:
-		host = string(buf[idDm0 : idDm0+buf[idDmLen]])
+		host = string(buf[idDm0 : idDm0+int(buf[idDmLen])])
 	}
 	// parse port
 	port := binary.BigEndian.Uint16(buf[reqEnd-2 : reqEnd])
diff --git a/ssh.go b/ssh.go
index 91c1bf3..58c0cbc 100644
--- a/ssh.go
+++ b/ssh.go
@@ -830,13 +830,13 @@ func (c *sshConn) RemoteAddr() net.Addr {
 }
 
 func (c *sshConn) SetDeadline(t time.Time) error {
-	return &net.OpError{Op: "set", Net: "ssh", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
+	return nil
 }
 
 func (c *sshConn) SetReadDeadline(t time.Time) error {
-	return &net.OpError{Op: "set", Net: "ssh", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
+	return nil
 }
 
 func (c *sshConn) SetWriteDeadline(t time.Time) error {
-	return &net.OpError{Op: "set", Net: "ssh", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
+	return nil
 }
diff --git a/ws.go b/ws.go
index d77c709..fa9c043 100644
--- a/ws.go
+++ b/ws.go
@@ -129,7 +129,7 @@ func (tr *wsTransporter) Handshake(conn net.Conn, options ...HandshakeOption) (n
 	if opts.WSOptions != nil {
 		wsOptions = opts.WSOptions
 	}
-	url := url.URL{Scheme: "ws", Host: opts.Addr, Path: "/ws"}
+	url := url.URL{Scheme: "ws", Host: opts.Host, Path: "/ws"}
 	return websocketClientConn(url.String(), conn, nil, wsOptions)
 }
 
@@ -210,7 +210,7 @@ func (tr *mwsTransporter) initSession(addr string, conn net.Conn, opts *Handshak
 	if opts.WSOptions != nil {
 		wsOptions = opts.WSOptions
 	}
-	url := url.URL{Scheme: "ws", Host: opts.Addr, Path: "/ws"}
+	url := url.URL{Scheme: "ws", Host: opts.Host, Path: "/ws"}
 	conn, err := websocketClientConn(url.String(), conn, nil, wsOptions)
 	if err != nil {
 		return nil, err
@@ -252,7 +252,7 @@ func (tr *wssTransporter) Handshake(conn net.Conn, options ...HandshakeOption) (
 	if opts.TLSConfig == nil {
 		opts.TLSConfig = &tls.Config{InsecureSkipVerify: true}
 	}
-	url := url.URL{Scheme: "wss", Host: opts.Addr, Path: "/ws"}
+	url := url.URL{Scheme: "wss", Host: opts.Host, Path: "/ws"}
 	return websocketClientConn(url.String(), conn, opts.TLSConfig, wsOptions)
 }
 
@@ -337,7 +337,7 @@ func (tr *mwssTransporter) initSession(addr string, conn net.Conn, opts *Handsha
 	if tlsConfig == nil {
 		tlsConfig = &tls.Config{InsecureSkipVerify: true}
 	}
-	url := url.URL{Scheme: "wss", Host: opts.Addr, Path: "/ws"}
+	url := url.URL{Scheme: "wss", Host: opts.Host, Path: "/ws"}
 	conn, err := websocketClientConn(url.String(), conn, tlsConfig, wsOptions)
 	if err != nil {
 		return nil, err