[OpenSIPS-Users] Fixed nated contact problem when using TLS

[Nauman Sulaiman]

Hi, we have a setup where we are using OpenSIPS as an out/inbound proxy. Te connection to the UAC is a TLS (port 5061) one and the connection fron OpenSIPS to third party voip provider is UDP (5060).  We have the TLS connection working and the UAC can successfully register with the provider. OpenSIPS is record routing twice once for the TLS route and another for the UDP. It seems to be bridging too. 

The problem we have is when we have an incoming invite (from voip provider) the contact header returned in the 200 OK from the UAC to OpensIPS has a private address say 192.168.1.20:5061, when opensips bridges this and the fixed nated contact is applied the correct external ip is sent 172.175.130.156:51056 but the port has changed. So the ACK when sent from provider back to OpenSIPS has the above address as req URI and then opensips can't route it back to the UAC because of the incorrect port. So main issue is OpenSIPS can't get the ACK back to UAC to establish the dialog. 

When there was no bridging (ie no TLS) the port was 5060 and fixed nated contact mapped it like this 172.175.130.156:5060 ie didn't change the port

How to get round this?

Thanks