[SR-Users] t_relay dying ?

[Jean Cérien]

Hi

While I'm trying to get the provider fix the SBC, I am implementing the
workaround.

Almost done here, storing and retrieving the correct address is fine, but
when I set my $ru to the corrected value (asterisk IP), the t_relay still
sends the packet to the kamailio IP -

$ru="sip:number at asteriskip:5060";
if (!t_relay()) {
....

Why would the t_relay forward to the kamailio IP and not the asterisk ?

Rgds
J


On Mon, Jan 8, 2018 at 11:49 AM, Jean Cérien <cerien.jean at gmail.com> wrote:

> Many, many thanks !
>
> I've posted the full dialog unredacted here: https://pastebin.com/EE9iwgZf
>
> The OK from Kamailio back to VOIP provider has
> Record-Route: <sip:KAMAILIOIP;lr=on;ftag=SD2rbta01-8dd0e72b-0016-0379-0000
> -0000;did=e0c.e0a1>
> Contact: <sip:NUMBER at ASTERISKIP:5060>
>
> So my understanding is that the ACK should be
> ACK sip:NUMBER at ASTERISKIP:5060 SIP/2.0
> ....
> and not
> ACK sip:NUMBER at KAMAILIOIP:5060 SIP/2.0
>
> Am I understanding correctly ?
>
> Rgds
> J
>
> On Mon, Jan 8, 2018 at 11:28 AM, Sebastian Damm <damm at sipgate.de> wrote:
>
>> Hi,
>>
>> On Mon, Jan 8, 2018 at 2:39 PM, Jean Cérien <cerien.jean at gmail.com>
>> wrote:
>>
>>>
>>> Thanks for this answer. The voip provider is not really eager to alter
>>> its SBC as it considers that the contact field is not mandatory in the ACK.
>>> The RFC states (section 8.1.1.8)
>>>
>>
>> The problem is not that the ACK doesn't carry a Contact header. The
>> problem is that the ACK is constructed incorrectly. This is what the RfC
>> says to UAC behavior (section 12.1.2):
>>
>> The route set MUST be set to the list of URIs in the Record-Route header
>> field from the response, taken in reverse order and preserving all URI
>> parameters. If no Record-Route header field is present in the response, the
>> route set MUST be set to the empty set. This route set, even if empty,
>> overrides any pre-existing route set for future requests in this dialog. *The
>> remote target MUST be set to the URI from the Contact header field of the
>> response.*
>>
>> This is what the carrier's SBC gets wrong. It doesn't address your
>> Asterisk but instead addresses your Kamailio, although the Contact of your
>> 200 OK (hopefully) contains the Asterisk IP.
>>
>> Please verify that your 200 OK going to the carrier actually does carry a
>> Contact header with the Asterisk IP, but if it does, section 12.1.2 of the
>> SIP RfC could help when arguing with the carrier.
>>
>> Regards
>> Sebastian
>>
>> _______________________________________________
>> Kamailio (SER) - Users Mailing List
>> sr-users at lists.kamailio.org
>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>
>>
>
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