diff --git a/flower/control.go b/flower/control.go
index f3716cf..01705c7 100644
--- a/flower/control.go
+++ b/flower/control.go
@@ -100,6 +100,7 @@ func (c *Controler) HandleNewTunnelRequest(req *msgpb.NewTunnelRequest) *msgpb.N
 		resp.ErrCode = msgpb.ErrCodeBadRegistryAddr
 		return resp
 	}
+	c.logger.Infof("New tunnel %s registered", req.TunnelHash)
 
 	c.proxies[req.TunnelHash] = proxy
 	go func() {
diff --git a/pkg/util/utils.go b/pkg/util/utils.go
index 19d01ec..ee333fe 100644
--- a/pkg/util/utils.go
+++ b/pkg/util/utils.go
@@ -68,7 +68,7 @@ func Host(req *http.Request) string {
 	if err != nil {
 		host = req.Host
 	}
-	return host
+	return strings.ToLower(host)
 }
 
 // Taken from https://play.golang.org/p/BDt3qEQ_2H
diff --git a/sun/registry/httpmux.go b/sun/registry/httpmux.go
index bcb37dc..84a51ac 100644
--- a/sun/registry/httpmux.go
+++ b/sun/registry/httpmux.go
@@ -41,7 +41,7 @@ func NewHTTPTunnelMuxer(domain string, addr string) (*HTTPTunnelMuxer, error) {
 	return &HTTPTunnelMuxer{
 		logger:   log.New("mux[http]"),
 		l:        l,
-		domain:   fmt.Sprintf(".%s", domain),
+		domain:   fmt.Sprintf(".%s", strings.ToLower(domain)),
 		registry: map[string]*httpConnListener{},
 		closed:   false,
 	}, nil
@@ -99,6 +99,7 @@ func (hm *HTTPTunnelMuxer) handleConn(conn net.Conn) {
 }
 
 func (hm *HTTPTunnelMuxer) Listen(subdomain string) (*httpConnListener, error) {
+	subdomain = strings.ToLower(subdomain)
 	hm.Lock()
 	defer hm.Unlock()
 	if hm.closed {
diff --git a/sun/registry/registry.go b/sun/registry/registry.go
index 5343dab..ca08db1 100644
--- a/sun/registry/registry.go
+++ b/sun/registry/registry.go
@@ -167,7 +167,6 @@ func (tr *TCPTunnelRegistry) makeTunnel(tracker *tracker.TunnelTracker, proto, s
 		tunnel Tunnel
 		err    error
 	)
-	// TODO(damnever): check the subdomain or listen address whether is legal
 	proto = strings.ToLower(proto)
 	switch proto {
 	case "http", "tcp":
diff --git a/sun/web/tunnel.go b/sun/web/tunnel.go
index f452326..bdeb722 100644
--- a/sun/web/tunnel.go
+++ b/sun/web/tunnel.go
@@ -73,7 +73,7 @@ func (s *Server) createTunnel(c echo.Context) error {
 
 	serverAddr := c.FormValue("server_addr")
 	if proto == "HTTP" {
-		serverAddr = fmt.Sprintf("%s.%s", serverAddr, user.targetName)
+		serverAddr = strings.ToLower(fmt.Sprintf("%s.%s", serverAddr, user.targetName))
 	} else {
 		serverAddr = fmt.Sprintf("0.0.0.0:%s", serverAddr)
 		if err := ValidateServerAddr(serverAddr); err != nil {