Desktop sharing or presentation during conference calls are not working when internal users with Lync 2010 clients are connecting to external users. If the client is S4B 2013/2016 on the internal user side, everything is working fine.
Here’s what I’m getting in the Lync client logs:
ms-client-diagnostics: 26; reason=”A federated call failed to establish due to a media connectivity failure where one endpoint is internal and the other is remote”;CallerMediaDebug=”application-sharing:ICEWarn=0x900029,LocalSite=172.x.x.x: 60037,LocalMR=10.x.x.x:3478,RemoteSite=132.245. 112.9:50057,RemoteMR=188.8.131.52:59085,PortRang e=60001:60040,RemoteMRTCPPort=59085,LocalLocation= 2,RemoteLocation=1,FederationType=1″
I also noticed that the public IP addresses our two Lync Edge servers and the NAT Public IP address of the affected clients are not shown in the candidate list in the INVITE packet sent by them to the remote client. All the candidates are “typ hosts” and are private IP addresses which are non-routable.
UDP 3478 and TCP 443 are open from internal client network to internal interface of Edge servers (we have two). Persistent static routes are setup properly in the edge servers so that they can reach back the clients.