I just wanted to modify the from header to be a E164 number that is recognized by Lync.

Is the port in the original From header? Is there a reason why I should not put the port in the from header?

That fixed the problem. Thank you!

The Windows firewall is disabled on the Lync Mediation server.

The initial INVITE from Brekeke SIP server goes to Lync mediation server port 5068.

A subsequent request from Brekeke SIP server is directed to port 5060 on the Lync mediation server. This is when the call setup fails.

Here's my dial plan rule: Matching patterns $request = ^INVITE $registered = false To = sip:(.+)@ $getUri(From) = sip:(.+) $port = (.+) Deploy patterns &net.sip.transport.follow.request = true $auth = false $continue = true $transport = TCP To = sip:%1@192.168.0.50:5068 From = sip:+12345678901;ext ...

Yes

1. Brekeke Product Name and Version: SIP Server ver 3.1.7.8 2. Java version: Java 7 Update 21 3. OS type and the version: Windows 2008 R2 4. UA (phone), gateway or other hardware/software involved: Polycom IP 501 5. Your problem: I am trying to use SIP Server to use legacy SIP devices (Polycom ...