We have recently setup a lync 2010 enviroment. We have a lync server (Standard Edition) and a lync edge server. The communication between internal clients performs as expected. External clients can connect and use the IM feature. The connection immediatly drops with a network error when we attempt to initiate a call.
The network is as follows:
Lync Server -- 10.104.220.178/24
Lync Edge Server -- 10.104.220.64/24 (Internal)
Lync Edge Server -- 10.104.250.2/24 (External)
We are NATing a public IP to the External address.
We are using internally assigned certificates for the LYNC and LYNC Edge Internal and a public SAN certificate. We get the following error when we start a lync communication session on the LYNC edge server. We believe that this may be the issue on why external client cannot communicate with our internal client.