[Blink] Improper outgoing interface representation on multihomed host

[Saul Ibarra Corretge]

Hi Alex,

On May 30, 2011, at 2:54 AM, Alex Balashov wrote:

> Greetings,
> 
> I am using Blink 0.2.7 on Linux.  I think I've run into a problem with improper selection of outbound network interface information to present in SIP initial request bodies.
> 
> I have a local network interface on a private network with address 10.0.42.211.  I also have an OpenVPN tunnel interface tun0 with address 10.5.30.13 over which a static route to my PBX is pinned in the system routing table, e.g.
> 
>   route add -host addr.of.pbx gw 10.5.30.12 dev tun0
> 
> I am trying to place calls with Blink through that PBX.
> 
> The problem is that even though the INVITE to the PBX does go out of tun0 from a Layer 3 perspective, obviously, all network and transport-layer address artifacts in the INVITE message body, such as, for example, the Via header, refer to the hardware interface address of 10.0.42.211.
> 

We are aware of the Via header issue, it's a limitation we have to live with, at least for now. Other fields such as c line should be correct, were they?

> From a practical perspective, I suppose the issue is somewhat academic;  it can be solved with a variety of conventional NAT-traversal strategies.  The PBX is Asterisk, so enabling nat=yes in particular would be an obvious fix.
> 

Yes, that's right. Actually only by doing rport should be enough. Please let us know if you found incorrect information in the SIP messages other than in the Via header.


Cheers,

-- 
Saul Ibarra Corretge
AG Projects