diff --git a/webrtc/Sdp.h b/webrtc/Sdp.h
index 6a20fc40..df3e529a 100644
--- a/webrtc/Sdp.h
+++ b/webrtc/Sdp.h
@@ -97,6 +97,10 @@ public:
     }
     virtual const char* getKey() const = 0;
 
+    void reset() {
+        value.clear();
+    }
+
 protected:
     mutable string value;
 };
diff --git a/webrtc/WebRtcTransport.cpp b/webrtc/WebRtcTransport.cpp
index 1a13c656..80b3d6ae 100644
--- a/webrtc/WebRtcTransport.cpp
+++ b/webrtc/WebRtcTransport.cpp
@@ -408,7 +408,22 @@ void WebRtcTransportImp::onStartWebRTC() {
 
 void WebRtcTransportImp::onCheckSdp(SdpType type, RtcSession &sdp){
     WebRtcTransport::onCheckSdp(type, sdp);
-    if (type != SdpType::answer || !canSendRtp()) {
+    if (type != SdpType::answer) {
+        return;
+    }
+
+    GET_CONFIG(string, extern_ip, RTC::kExternIP);
+    for (auto &m : sdp.media) {
+        m.addr.reset();
+        m.addr.address = extern_ip.empty() ? SockUtil::get_local_ip() : extern_ip;
+        m.rtcp_addr.reset();
+        m.rtcp_addr.address = m.addr.address;
+        m.rtcp_addr.port = _socket->get_local_port();
+        m.port = m.rtcp_addr.port;
+        sdp.origin.address = m.addr.address;
+    }
+
+    if (!canSendRtp()) {
         return;
     }