diff --git a/constant/metadata.go b/constant/metadata.go
index 4a361dfb..4bb02885 100644
--- a/constant/metadata.go
+++ b/constant/metadata.go
@@ -50,7 +50,3 @@ func (m *Metadata) String() string {
 func (m *Metadata) Valid() bool {
 	return m.Host != "" || m.IP != nil
 }
-
-func (m *Metadata) NeedLoopUpHost() bool {
-	return m.Source == REDIR
-}
diff --git a/dns/client.go b/dns/client.go
index 29b4207c..cfae7b9f 100644
--- a/dns/client.go
+++ b/dns/client.go
@@ -219,6 +219,10 @@ func (r *Resolver) resolve(client []*nameserver, msg *D.Msg) <-chan *result {
 	return ch
 }
 
+func (r *Resolver) IsMapping() bool {
+	return r.mapping
+}
+
 type NameServer struct {
 	Net  string
 	Addr string
diff --git a/tunnel/tunnel.go b/tunnel/tunnel.go
index 96920818..2663ca31 100644
--- a/tunnel/tunnel.go
+++ b/tunnel/tunnel.go
@@ -107,11 +107,15 @@ func (t *Tunnel) resolveIP(host string) (net.IP, error) {
 	return t.resolver.ResolveIP(host)
 }
 
+func (t *Tunnel) needLookupIP() bool {
+	return t.hasResolver() && t.resolver.IsMapping()
+}
+
 func (t *Tunnel) handleConn(localConn C.ServerAdapter) {
 	defer localConn.Close()
 	metadata := localConn.Metadata()
 
-	if metadata.NeedLoopUpHost() && t.hasResolver() {
+	if t.needLookupIP() {
 		host, exist := t.resolver.IPToHost(*metadata.IP)
 		if exist {
 			metadata.Host = host