diff --git a/core/AmB2BSession.cpp b/core/AmB2BSession.cpp
index 83354eab..58baae92 100644
--- a/core/AmB2BSession.cpp
+++ b/core/AmB2BSession.cpp
@@ -276,6 +276,15 @@ void AmB2BSession::createFakeReply(const AmMimeBody *sdp,   AmMimeBody& reply_bo
   ILOG_DLG(L_DBG, "created pending INVITE reply body: %s\n", body_str.c_str());
 }
 
+static void sdp2body(const AmSdp &sdp, AmMimeBody &body)
+{
+  string body_str;
+  sdp.print(body_str);
+  AmMimeBody *s = body.hasContentType(SIP_APPLICATION_SDP);
+  if (s) s->parse(SIP_APPLICATION_SDP, (const unsigned char*)body_str.c_str(), body_str.length());
+  else body.parse(SIP_APPLICATION_SDP, (const unsigned char*)body_str.c_str(), body_str.length());
+}
+
 void AmB2BSession::acceptPendingInvite(AmSipRequest *invite)
 {
   // reply the INVITE with fake 200 reply
@@ -292,9 +301,44 @@ void AmB2BSession::acceptPendingInvite(AmSipRequest *invite)
 void AmB2BSession::acceptPendingInviteB2B(const AmSipRequest& invite)
 {
   const AmMimeBody *sdp = invite.body.hasContentType(SIP_APPLICATION_SDP);
-
   AmSipReply n_reply;
-  createFakeReply(sdp, n_reply.body);
+
+  /* local sdp, which was already learned before */
+  AmSdp remote_sdp = dlg->getRemoteSdp();
+
+  unsigned int remote_port = 0;
+
+  if (dlg->getRemoteMediaPort() > 0) {
+    ILOG_DLG(L_DBG, "Using remotely seen SDP port for faking this reply: '%d'\n", dlg->getRemoteMediaPort());
+    remote_port = dlg->getRemoteMediaPort();
+  }
+  else if (!remote_sdp.media.empty()) {
+    /* take first possible media and re-use its port */
+    SdpMedia remote_sdp_media = remote_sdp.media.front();
+    if (remote_sdp_media.port > 0) {
+      ILOG_DLG(L_DBG, "Using remotely seen SDP port for faking this reply: '%d'\n", remote_sdp_media.port);
+      remote_port = remote_sdp_media.port;
+    }
+  }
+
+  if (remote_port > 0) {
+    /* create fake AmSdp from AmMimeBody */
+    AmSdp fake_sdp;
+    AmMimeBody fake_mimebody;
+    fake_sdp.parse((const char *)sdp->getPayload());
+
+    ILOG_DLG(L_DBG, "Using local SDP port for faking this reply: '%d'\n", remote_port);
+    for (auto it = fake_sdp.media.begin(); it != fake_sdp.media.end(); ++it)
+    {
+      it->port = remote_port;
+    }
+
+    sdp2body(fake_sdp, fake_mimebody);
+    createFakeReply(&fake_mimebody, n_reply.body);
+  }
+  else {
+    createFakeReply(sdp, n_reply.body);
+  }
 
   n_reply.code = 200;
   n_reply.reason = "OK";
diff --git a/core/AmOfferAnswer.cpp b/core/AmOfferAnswer.cpp
index 28797b29..e20b2ad1 100644
--- a/core/AmOfferAnswer.cpp
+++ b/core/AmOfferAnswer.cpp
@@ -58,7 +58,8 @@ AmOfferAnswer::AmOfferAnswer(AmSipDialog* dlg)
     sdp_remote(),
     sdp_local(),
     dlg(dlg),
-    force_sdp(true)
+    force_sdp(true),
+    remote_port_seen(0)
 {
   
 }
@@ -85,6 +86,11 @@ const AmSdp& AmOfferAnswer::getRemoteSdp() const
   return sdp_remote;
 }
 
+const unsigned int& AmOfferAnswer::getRemoteMediaPort() const
+{
+  return remote_port_seen;
+}
+
 /** State maintenance */
 void AmOfferAnswer::saveState()
 {
@@ -225,6 +231,12 @@ int AmOfferAnswer::onReplyIn(const AmSipReply& reply)
           dlg->onSdpReceived(true);
         }
 
+        if (!sdp_remote.media.empty())
+        {
+          SdpMedia remote = sdp_remote.media.front();
+          remote_port_seen = remote.port;
+        }
+
       } else {
         bool is_reliable = reply.code >= 200 || key_in_list(getHeader(reply.hdrs, SIP_HDR_REQUIRE), SIP_EXT_100REL);
         saveState();
@@ -274,6 +286,12 @@ int AmOfferAnswer::onRxSdp(unsigned int m_cseq, const string& m_remote_tag,
     sdp_remote.clear();
   }
 
+  if (!sdp_remote.media.empty())
+  {
+    SdpMedia remote = sdp_remote.media.front();
+    remote_port_seen = remote.port;
+  }
+
   if(err_code == 0) {
 
     switch(state) {
diff --git a/core/AmOfferAnswer.h b/core/AmOfferAnswer.h
index f0c19254..eea096a5 100644
--- a/core/AmOfferAnswer.h
+++ b/core/AmOfferAnswer.h
@@ -53,6 +53,9 @@ private:
   AmSdp        sdp_remote;
   AmSdp        sdp_local;
 
+  /* saved remote port */
+  unsigned int remote_port_seen;
+
   AmSipDialog* dlg;
 
   /** Should SDP generation be forced when not required by standards? */
@@ -79,6 +82,7 @@ public:
   void setState(OAState n_st);
   const AmSdp& getLocalSdp() const;
   const AmSdp& getRemoteSdp() const;
+  const unsigned int& getRemoteMediaPort() const;
 
   void clear();
   void clearTransitionalState();
diff --git a/core/AmSipDialog.h b/core/AmSipDialog.h
index 16d7c1c9..56e01fa7 100644
--- a/core/AmSipDialog.h
+++ b/core/AmSipDialog.h
@@ -134,6 +134,7 @@ protected:
 
   const AmSdp& getLocalSdp() { return oa.getLocalSdp(); }
   const AmSdp& getRemoteSdp() { return oa.getRemoteSdp(); }
+  const unsigned int& getRemoteMediaPort() { return oa.getRemoteMediaPort(); }
 
   /**
    * Reliable provisional replies