[Users] Openser and NATed users

Hi guys!

I try to use OpenSER with NATed-users and now I have some problem. No I'll try to explain it.

I have the following network scheme:

mySIP-phone_behind_NAT --> NAT --> OpenSER --> OtherProxy --> other_SIP_phone

mySIP-phone_behind_NAT have some knowledges about external NAT_ip so it successfully registered on OpenSER using nathelper module and location table have new record looks like:

user@mydomain Contact: user@NAT_ip:5060 Received: NAT_ip:NAT_port

Then mySIP-phone_behind_NAT send new INVITE with Contact=user@NAT_ip:5060 OpenSER fixup this Contact using fix_nated_contact() and send INVITE to OtherProxy with Contact=user@NAT_ip:NAT_port;nat=yes

Then 200OK and ACK successfully traversed via OpenSER and dialog esteblished.

Then other_SIP_phone sends BYE request using R-URI learned from previous INVITE Contact-header=ser@NAT_ip:NAT_port;nat=yes OpenSER rewrite this R-URI to user@NAT_ip:NAT_port and send it using t_relay(). The packet goes to NAT_ip:NAT_port but mySIP-phone_behind_NAT sends "404 Not found" because it does not know anything about user@NAT_ip:NAT_port -- it expected user@NAT_ip:5060 as sended in first INVITE.

So, my question is: is this my misconfiguration or incorrect logic understanding ?

I have some ideas how to fix this problem, for eaxample: when I got INVITE from mySIP-phone_behind_NAT I must rewrite Contact to user@mydomain (assuming that requests to mydomain goes to OpenSER always). Then if OpenSER got BYE from other_SIP_phone it will lookup() and restore Contact and Received info. But I have problem again: If I rewrite R-URI to Contact and t_relay() it -- packet will be discarded by NAT because it does not anything about port 5060. If I rewrite R-URI using Received info I will get problem discribed early.

Feature request "Allow AVP in t_relay()" (published in Tracker) will solve this problem

Any suggestion?