Hello,

Apparently, this is the way the code works:

t_reply.c:

                        if (relayed_code==503 && tm_remap_503_500){

                                /* replace a final 503 with a 500:

                                 * generate a "FAKE" reply and a new to_tag (for easier

                                 *  debugging)*/

Lets see if maybe others can comment as well. Otherwise you could just open an issue on our tracker, it is probably not that hard to change this.

Cheers,

Henning

--

Henning Westerholt – https://skalatan.de/blog/

Kamailio services – https://gilawa.com

From: sr-users <sr-users-bounces@lists.kamailio.org> On Behalf Of Gerry | Rigatta
Sent: Wednesday, July 22, 2020 8:58 PM
To: Kamailio (SER) - Users Mailing List <sr-users@lists.kamailio.org>
Subject: [SR-Users] bug ? remap_503_500 breaks dialogs

Hi,

I am using Kamailio 5.2. 

Apparently the remapping of 503 to 500 codes in the tm module does also change the to-tag. This behaviour breaks dialogs with yate and therefore calls hang and the 503 remains unacknowledged. After disabling the 503 to 500 remapping with modparam("tm", "remap_503_500", 0) all works fine again.

Changing the to-tag in a dialog seems to contradict RFC3261, or do I see this wrongly?

12 Dialogs

A dialog is identified at each UA with a dialog ID, which consists of a Call-ID value, a local tag and a remote tag…"

Thanks for looking into this.

Gerry