T22P - OpenVPN with multiple accounts

[paulszat]

I've got a specific situation where I need to add two SIP accounts to a telephone. One is accessible on the local LAN and the other is only accessible via an OpenVPN connection. The OpenVPN connection works perfectly and I'm only pushing the necessary routes for the phone to access the external SIP account.

The internal local LAN account registers fine with the SIP server (3CX) but there's no audio. Looking at the log files it appears the phone is sending the IP of the OpenVPN tunnel to the local account rather than sending the IP of the LAN interface. Excerpt from the 3CX log file here:

7-Oct-2014 13:56:01.001 NAT/ALG check:L:1927.1[Extn:114] REQUEST 'INVITE' - some of SIP/SDP headers may contain inconsistent information or modified by intermediate hop
SIP contact header is not equal to the SIP packet source(IP:port):
Contact address:172.16.100.6:5063
Received from :10.105.37.219:5063
Media session IP ('c=' attribute) is not equal to the SIP packet source(IP:port):
Media session IP: 172.16.100.6
Received from: 10.105.37.219


This seems to me to be a bug as the phone shouldn't send that IP in the SIP headers unless the traffic is exiting through the VPN interface.

Thanks

Paul