#14 In-correct VIA header for MHOMED Proxy

[Jim Burke]

If a UAC is registered via an external IP address, when using t_relay(ip_address) to force an INVITE message to internal IP address after location_lookup the first Via header is the external IP and not the internal IP address used in the t_relay command.

This results in messages returned from the B2BUA ie 100 "Trying" to be sent to the external IP and not the internal IP address this causes the calls to fail.

OS: Fedora Core 5
version: opensips 1.4.1-tls (i386/linux)
flags: STATS: Off, USE_IPV6, USE_TCP, USE_TLS, DISABLE_NAGLE, USE_MCAST, SHM_MEM, SHM_MMAP, PKG_MALLOC, F_MALLOC, FAST_LOCK-ADAPTIVE_WAIT
ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535
poll method support: poll, epoll_lt, epoll_et, sigio_rt, select.
svnrevision: 2:4624M
@(#) $Id: main.c 4504 2008-07-29 09:55:03Z bogdan_iancu $
main.c compiled on 12:02:51 Aug 26 2008 with gcc 4.1.1

If you need some further information please let me know.

Regards,
Jim

[Bogdan-Andrei Iancu]

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Hi Jim,

So, your scenario is:
1) receive call and force the internal ip
2) do lookup("location") where destination is a device registered with the external Ip

I'm asking as lookup("location") internally forces the interface to be used to the one used to receive the REGISTER from the device. So, if the device registered via external IP, all the calls to it will be delivered via the external interface.

Maybe a more clear description of your flow will help in understanding the problem.

Regards,
bogdan

[Jim Burke]

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Hi Bogdan,

Thanks for your follow-up!

Server Setup:
Duplicated linux servers running opensips bound to external and internal IP on port 5060 and b2bua bound to internal IP address on port 5070. REGISTER messages have PATH included and duplicated to second server so NAT UAC are handled correctly.

Call scenario:

1, A and B UAC registered via external IP address
2, A calls B, INVITE incoming via external IP address.
3, After checking for local number a lookup location is performed.
4, If user is online we bill the call then force the INVITE via internal IP to B2BUA to handle call timing.
5, B2BUA routes the call back to Opensips and out via external IP to B.

Regards,
Jim

[Bogdan-Andrei Iancu]

Hi Jim,

As said, the lookup("location") is automatically trying to set as outbound interface the same interface as the one the REGISTER was received on - in your case, the external interface. But you send the call via the internal interface - to route the call to B2BUA.

Try doing a force_send_socket("inernal_interface") before sending the call to B2BUA.
http://www.opensips.org/index.php?n=Resources.DocsCoreFcn

Regards,
Bogdan

[Jim Burke]

Hi Bogdan,

Thanks! Your suggestion resolves the issue.

Regards,
Jim