Two external phones on same connection

[Sha1a]

Hello, 

I have a Cisco 7940 connected to our server from my home office, everything works perfect. I now have the need for two phones in my home office. I purchased a second phone, a Cisco 7945G. I have configured it fine and both phones are showing as registerd on the server and can make out going calls fine. However incoming calls are now failing. Now when you call either extension set up in my home office you get a "called number does not exsist" message. 

The server log is saying that the extension cannot be found. 

Any ideas? I'm an guessing it's a port issue?  

Thanks in advance for any help. 

 

[eagle2]

All fixed....

Main problem was using a Basic Router provided by Sky in the external office...

Installed a Netgear Modem and a Open Source Asus Router with DD-WRT loaded, Fixed all the NAT problems of only being able to have one phone fully working.

All this is about the remote router -- the new router you installed is obviously SIP ALG compatible and is handling SIP/SDP/RTP packets correctly.