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RE: [reSIProcate] DNS question


On Fri, 2006-01-13 at 15:59 +0000, Robert Mansfield wrote:
> Thanks for the response. The application is constructing the Via header
> using an V4 IP address within a test environment.
> 
> So Via: SIP/2.0/UDP 10.0.0.1;branch=... 
> 
> However the AoR in the INVITE is constructed using a sip url
> 
> INVITE sip:user@xxxxxxxxxxxxxxx

I'm not sure I understand what you're trying to do.  The application is
functioning as a UA, and it's originating the INVITE?  If that's the
case, then there's no reason for the application to insert a Via, which
would describe how to get to the *previous* SIP agent (which doesn't
exist).  ReSIProcate will (should?), of course, add another Via
describing how the INVITE gets sent to its next hop, but that would be a
second Via in the message.

>       8.1.1.7 Via
> 
>        The Via header field indicates the transport used for the transaction
>        and identifies the location where the response is to be sent.  A Via
>        header field value is added only after the transport that will be
>        used to reach the next hop has been selected (which may involve the
>        usage of the procedures in [4]).

This can be read several ways.  The common practice is to always give an
IP address, but the grammar allows domain names, and in some redundant
systems, you would want to use domain names rather than IP addresses.

Dale