Change 'Contact' Field IP not works as expected

[efthimis]

Hello,
I have installed the 3CX phone system on a virtual machine. I have 2 Network cards. One local(for IP phone registration) and one global for VoIP provider registration.
In order to register to my VoIP provider i set the field "Which IP to use in 'Contact' and 'Connection' SIP fields" in advanced settings to voip provider menu with my public IP. It registers ok but incoming calls hangs out after 31sec. I use wireshark and i see that all messages (register, ringing etc) have the public IP in contant field in SIP header. The only exception is message 200 OK where the contact field takes the local IP. I use the 3CX version 12.5. Is it a bug?
If i change the IP from settings->network and set as external my public IP it works ok, but then i have problems with phone registration.
Is there any solution here? Thanks in advance.

 

[leejor]

If you do a search through the forum, there have been a number of posts on this topic.

This one seems to have found a solution to their particular issue. I'm not sure if it will apply to yourt.

http://www.3cx.com/forums/two-nic-server-16652.html

 

[efthimis]

Thanks for the reply,

I tried but it not worked for me. The routing is fine, the only problem i think is in sip header where the contact field takes the local ip.

 

[leejor]

Did you come across this?

http://www.3cx.com/blog/voip-howto/nat-stun-network-configuration/