[OpenSIPS-Users] Downstream proxy rewriting contact header

[Nauman Sulaiman]

Hi, using Opensips 1.6.2 we have the following setup.

UA1----Opensips Proxy ------- P1 ------ P2 ------ UA2

Proxy P1 is rewriting contact header sent by opensips in 180 and 200K response  to INVITE from UA2 to UA1. All proxies are record-routing. P1 seems to assume all requests are from behind NAT and rewrites the contact header with source IP ie that of Opensips proxy. The result is UA2 ACK is routed only to Opensips proxy and does not reach UA1. Is there any i can handle this in the Opensips proxy to account for behaviour of P1. 

Thanks