Recently I had to troubleshoot a newly installed Sametime environment for a small deployment.
All WebSphere components installed on 1 box with 3 ip addresses assigned to 1 Nic on Windows 2008 R2 SP1
Point to point video was working, however adding a third person or using Audio and Video from the meeting center would not work.
Strange… After some investigation, it looked like the Media Server services and Proxy server services were all listening on the Meeting servers address instead of there assigned ip.
The first assigned IP (I thought to be the default for outgoing traffic) x.x.x.179 System Console and Media Server. Proxy was assigned to x.x.x.172 and meeting to x.x.x.173
All were listening on x.x.x.172
Strange, if all listening on 1 it should be the default IP x.x.x.179 and certainly not x.x.x.172
Then I found this article http://www.confusedamused.com/notebook/source-ip-address-preference-with-multiple-ips-on-a-nic
On windows 2003 the first Ip address becomes the default for outgoing traffic.
Microsoft decided to change this behaviour in Windows 2008 where the IP with the lowest digit is default for outgoing traffic (wow that makes sense)
So I ended up shutting down all services, removing the 172 and 173 address from the nic and re-inserting them using following command:
netsh int ipv4 add address “Local Area Connection” x.x.x.172 255.255.255.0 SkipAsSource=true
netsh int ipv4 add address “Local Area Connection” x.x.x.173 255.255.255.0 SkipAsSource=true
Restarted al services
Everything started working as expected