[Serusers] Register to SER with UDP

[Andrei Pelinescu-Onciul]

On Aug 15, 2008 at 10:30, Steven Wu <Steven.Wu at teleca.com> wrote:
> Hi All,
>  
> Does SIP server at iptel.org support UDP register?

Of course it does, most of the users use UDP.

> When my UA rigister to iptel.org whith UDP, the 401 response always replied by SER at port
> 100xx(example 10028). But in my contact of rigister port assigned to 5060.
> So, my UA can't recive the 401 response, register failure.

The reply does not go to the contact address (which is used only for
subsequent requests), but to the source ip of the request and the port
from via or from the via rport parameter.
Because of the large number of UAs behind NAT, that do not support the
rport extension, but still support symmetric signalling we force rport
behaviour for everybody (which means we send back to the source port of
the request). If your UA does not support symmetric signalling
(which means it will never work from behind a NAT unless you manually
 forward ports on your NAT box) it would explain your problems, but I
 would need a captured message to tell for sure (you can send it to me
 privately).
If I were you I would upgrade the UA, or check if symmetric signalling
can be turned on from its config (it's a basic feature that any UA
should support by default).

>  
> But use TCP everyting is OK?

On TCP the reply goes back on the same connection on which the request
was received and probably your UA expects this and does not close the
TCP connection.

>  
> Can anyone give me help? 


Andrei