[OpenSIPS-Users] Issues with ACK with 2 NIC opensips + GW behind NAT

[Iñaki Baz Castillo]

2009/5/4 oso che bol <ndlgroup1 at gmail.com>:
> Hi IBC, bogdan,
>
> I capture on UA 1 (caller)
> 1. Invite from caller send to opensips
> 2. opensips send to caller 100 Give a try
> 3. Opensips send 200 OK with SDP to Caller
> 4. RTP setup between Caller and RTPPRoxy
> 5. Caller send ACK to SIP_GW_PRIVATE_IP (that break here )
>
> Could you please explain why ACK do not go through Opensips?
> Thanks,

First of all, I don't see the 200 arriving to caller in the SIP flow
you pasted (probably because you just did the capture for one
interface).

Anyway I see a *bug* in the 200 sent by the GW: It doesn't contain
"Route" header !!!
It should include it since the INVITE arriving to it did contain "Record-Route".

So, the 200 arrives to the caller with NO "Route" headers and the
following Contact:
  Contact: sip:SIPGW_PRIVATE_IP.

So, the caller would sent the ACK *directly* to SIPGW_PRIVATE_IP, and
of course, it's unreachable from its LAN.

The problem is in the GW which doesn't add "Route" header to the 200.
This "Route" should mirror the value of the received "Record-Route"
headers in the first INVITE.

PD:  Please, *don't* add Bogdan in the CC of all your mails, he *does*
read this maillist. Just add the maillist as recipient of your
questions.

Regards.


-- 
Iñaki Baz Castillo
<ibc at aliax.net>