[SR-Users] Proxying INVITE message without port information in R-URI

[Klaus Darilion]

Am 19.01.2011 18:21, schrieb Vikram Ragukumar:
> Klaus, Alex,
>
> Thank you for your replies.
>
>> Does the SIP server perform NAT traversal?
>>
>> Does the SIP proxy perform NAT traversal?
>
> The SIP proxy performs NAT traversal.

How? Does it change the Contact header?

>
>> How does the SIP server route the INVITE requests? Does it route based
>> on registered Contact or does it route them statically to the SIP proxy?
>> Depending on the routing behavior on the SIP server you can build a
>> workaround on the proxy.
>
> The SIP server routes INVITES based on registered Contact.

So the SIP server is the registrar?

The contact usually is the IP address of the client. So, if you the SIP 
server routes based on the contact header, it should send the INVITE 
directly to the client not to the proxy. Somehow this all does not fit 
together.

> What workaround needs to be implemented at the proxy so that the INVITE
> is forwarded to the appropriate port number ?

It depends on how is the registrar - proxy or the SIP server.

The workaround also depends on the respective buggy behavior of the sip 
server (if there is one at all).

I think it is not possible to further debug this problem without a 
complete trace of the scenario:

ngrep -W byline -t -d any -P "" port 5060

regards
klaus