[OpenSIPS-Users] Topology hiding, media proxy and the SDP o= line

[Saúl Ibarra Corretgé]

Hi,

On May 10, 2012, at 10:35 AM, Jacek Konieczny wrote:

> Hello,
> 
> I have an opensips with mediaproxy configured as a SIP gateway between
> our PBXes and PSTN trunk providers. I would like to hide our internal
> network topology, though I would prefer not to change whole
> configuration to B2B. Opensips 1.7 provided the topology_hiding()
> function in the dialog module, which mostly does the trick.
> 
> Though, a simple detail remained in our requests, that I don't like 
> – the original IP address in the 'o=' line of the request SDP body ('c='
> line is already modified for the media proxy).
> 
> Is there any way to do anything about this? It seems this IP address
> does not provide any important information.
> 

The o= field contains information about the originator of the session (http://tools.ietf.org/html/rfc4566#section-5.2) and it's not used for routing, so you may leave it as-is. If you really want to hide it you can probably use something from the textops/sipmsgops modules to do it, but you'll need to remember to do it all the time, because some strict parser may reject your request if you change the origin line in the middle of a dialog.


Regards,

--
Saúl Ibarra Corretgé
AG Projects