diff --git a/client.go b/client.go
index 56622ec..0c1fb43 100644
--- a/client.go
+++ b/client.go
@@ -19,7 +19,7 @@ const (
 
 func NewClient(addr string, server string, target string, timeout int, key int,
 	tcpmode int, tcpmode_buffersize int, tcpmode_maxwin int, tcpmode_resend_timems int, tcpmode_compress int,
-	tcpmode_stat int, open_sock5 int) (*Client, error) {
+	tcpmode_stat int, open_sock5 int, maxconn int) (*Client, error) {
 
 	var ipaddr *net.UDPAddr
 	var tcpaddr *net.TCPAddr
@@ -62,6 +62,7 @@ func NewClient(addr string, server string, target string, timeout int, key int,
 		tcpmode_compress:      tcpmode_compress,
 		tcpmode_stat:          tcpmode_stat,
 		open_sock5:            open_sock5,
+		maxconn:               maxconn,
 	}, nil
 }
 
@@ -70,6 +71,7 @@ type Client struct {
 	rtt            time.Duration
 	interval       *time.Ticker
 	workResultLock sync.WaitGroup
+	maxconn        int
 
 	id       int
 	sequence int
@@ -272,9 +274,15 @@ func (p *Client) AcceptTcpConn(conn *net.TCPConn, targetAddr string) {
 	p.workResultLock.Add(1)
 	defer p.workResultLock.Done()
 
-	uuid := UniqueId()
 	tcpsrcaddr := conn.RemoteAddr().(*net.TCPAddr)
 
+	if p.localIdToConnMapSize >= p.maxconn {
+		loggo.Info("too many connections %d, client accept new local tcp fail %s", p.localIdToConnMapSize, tcpsrcaddr.String())
+		return
+	}
+
+	uuid := UniqueId()
+
 	fm := NewFrameMgr(p.tcpmode_buffersize, p.tcpmode_maxwin, p.tcpmode_resend_timems, p.tcpmode_compress, p.tcpmode_stat)
 
 	now := time.Now()
@@ -484,6 +492,10 @@ func (p *Client) Accept() error {
 		now := time.Now()
 		clientConn := p.getClientConnByAddr(srcaddr.String())
 		if clientConn == nil {
+			if p.localIdToConnMapSize >= p.maxconn {
+				loggo.Info("too many connections %d, client accept new local udp fail %s", p.localIdToConnMapSize, srcaddr.String())
+				continue
+			}
 			uuid := UniqueId()
 			clientConn = &ClientConn{ipaddr: srcaddr, id: uuid, activeRecvTime: now, activeSendTime: now, close: false}
 			p.addClientConn(uuid, srcaddr.String(), clientConn)
diff --git a/cmd/main.go b/cmd/main.go
index a909d56..077b97c 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -71,6 +71,9 @@ Usage:
 
     -sock5    开启sock5转发，默认0
               Turn on sock5 forwarding, default 0 is off
+
+    -maxconn  最大连接数，默认1000
+              the max num of connections, default 1000
 `
 
 func main() {
@@ -90,6 +93,7 @@ func main() {
 	tcpmode_stat := flag.Int("tcp_stat", 0, "print tcp stat")
 	loglevel := flag.String("loglevel", "info", "log level")
 	open_sock5 := flag.Int("sock5", 0, "sock5 mode")
+	maxconn := flag.Int("maxconn", 0, "max num of connections")
 	flag.Usage = func() {
 		fmt.Printf(usage)
 	}
@@ -132,7 +136,7 @@ func main() {
 	loggo.Info("key %d", *key)
 
 	if *t == "server" {
-		s, err := pingtunnel.NewServer(*key)
+		s, err := pingtunnel.NewServer(*key, *maxconn)
 		if err != nil {
 			loggo.Error("ERROR: %s", err.Error())
 			return
@@ -143,8 +147,7 @@ func main() {
 			loggo.Error("Run ERROR: %s", err.Error())
 			return
 		}
-	}
-	if *t == "client" {
+	} else if *t == "client" {
 
 		loggo.Info("type %s", *t)
 		loggo.Info("listen %s", *listen)
@@ -161,7 +164,7 @@ func main() {
 
 		c, err := pingtunnel.NewClient(*listen, *server, *target, *timeout, *key,
 			*tcpmode, *tcpmode_buffersize, *tcpmode_maxwin, *tcpmode_resend_timems, *tcpmode_compress,
-			*tcpmode_stat, *open_sock5)
+			*tcpmode_stat, *open_sock5, *maxconn)
 		if err != nil {
 			loggo.Error("ERROR: %s", err.Error())
 			return
@@ -173,6 +176,8 @@ func main() {
 			loggo.Error("Run ERROR: %s", err.Error())
 			return
 		}
+	} else {
+		return
 	}
 	for {
 		time.Sleep(time.Hour)
diff --git a/server.go b/server.go
index 6cab990..1fcb7f3 100644
--- a/server.go
+++ b/server.go
@@ -10,10 +10,11 @@ import (
 	"time"
 )
 
-func NewServer(key int) (*Server, error) {
+func NewServer(key int, maxconn int) (*Server, error) {
 	return &Server{
-		exit: false,
-		key:  key,
+		exit:    false,
+		key:     key,
+		maxconn: maxconn,
 	}, nil
 }
 
@@ -22,15 +23,17 @@ type Server struct {
 	key            int
 	interval       *time.Ticker
 	workResultLock sync.WaitGroup
+	maxconn        int
 
 	conn *icmp.PacketConn
 
 	localConnMap sync.Map
 
-	sendPacket     uint64
-	recvPacket     uint64
-	sendPacketSize uint64
-	recvPacketSize uint64
+	sendPacket       uint64
+	recvPacket       uint64
+	sendPacketSize   uint64
+	recvPacketSize   uint64
+	localConnMapSize int
 
 	echoId  int
 	echoSeq int
@@ -118,6 +121,11 @@ func (p *Server) processPacket(packet *Packet) {
 	localConn := p.getServerConnById(id)
 	if localConn == nil {
 
+		if p.localConnMapSize >= p.maxconn {
+			loggo.Info("too many connections %d, server connected target fail %s", p.localConnMapSize, packet.my.Target)
+			return
+		}
+
 		if packet.my.Tcpmode > 0 {
 
 			addr := packet.my.Target
@@ -449,8 +457,13 @@ func (p *Server) checkTimeoutConn() {
 }
 
 func (p *Server) showNet() {
-	loggo.Info("send %dPacket/s %dKB/s recv %dPacket/s %dKB/s",
-		p.sendPacket, p.sendPacketSize/1024, p.recvPacket, p.recvPacketSize/1024)
+	p.localConnMapSize = 0
+	p.localConnMap.Range(func(key, value interface{}) bool {
+		p.localConnMapSize++
+		return true
+	})
+	loggo.Info("send %dPacket/s %dKB/s recv %dPacket/s %dKB/s %dConnections",
+		p.sendPacket, p.sendPacketSize/1024, p.recvPacket, p.recvPacketSize/1024, p.localConnMapSize)
 	p.sendPacket = 0
 	p.recvPacket = 0
 	p.sendPacketSize = 0