I am trying to setup my N95 (a truly great phone!) with our SIP IP-PBX, and the N95 is not able to register with the IP-PBX. I created a SIP profile and Internet Telephone profile manually (via Tools->Settings) and I have tried several combinations to test my network setup and connection, including the following:

1. The N95 is able to register with Truphone and Gizmo. Both services work correctly, including incoming and outgoing calls.

2. Our SIP IP-PBX works correctly with other SIP endpoints (h/w and s/w based).

3. I have tried our IP-PBX in both a remote mode (across the WAN) and local mode (within the LAN). Neither work.

4. I have tried monitoring the SIP traffic (using Ethereal) to the local IP-PBX server when running in the LAN, and cannot even see the attempted registration requests to the local server. Note that I am able to see HTTP requests from the N95 when connecting to the web server running on the same local server as the IP-PBX.

Many thanks for your help.