Hello Benoit, actually - thinking a bit more about it, I think that the second INVITE should just not contain a To-tag, as no dialog has been established yet.
Refer to RFC 4028, Section 13 for the example call flow. So, it seems that A is indeed misbehaving to add a To-tag to the second INVITE. Cheers, Henning > -----Original Message----- > From: Henning Westerholt > Sent: Montag, 1. Dezember 2025 21:08 > To: 'Kamailio (SER) - Users Mailing List' <[email protected]> > Cc: Benoit Panizzon <[email protected]> > Subject: RE: [SR-Users] Re: How to correctly generate a 181 Call is being > forwarded reply? > > Hello, > > Sorry, but I don't fully understand the problem here. According to RFC 3161 > the 181 replies need to have a To-tag. > > According to RFC 5359 the To-Tag has a different value as later then used e.g. > in the 200 OK confirmation. > > The loose_route function usually doesn't check for transactions, as already > pointed out, but checks for Route header. > > So, if your later INVITE with a To-Tag don't work, you probably should > investigate why the routing information is missing in the second INVITE, or > add a special handling for re-INVITEs to your cfg when there is no routing > information. > > Cheers, > > Henning > > > -----Original Message----- > > From: Benoit Panizzon via sr-users <[email protected]> > > Sent: Montag, 1. Dezember 2025 15:14 > > To: Benoit Panizzon via sr-users <[email protected]> > > Cc: Benoit Panizzon <[email protected]> > > Subject: [SR-Users] Re: How to correctly generate a 181 Call is being > > forwarded reply? > > > > Hi again > > > > > I don't seem to get it working as expected - still trying to figure out > > > what and where the call fails. > > > > I think I have found what goes wrong. > > > > A => B => CFW => C > > > > C has MIN-SE: 900 > > A is initially sending Sestion-Timer: 600 > > > > Without 181 reply: > > > > C replies with 422 Timer too Small Min-SE: 900 > > This 422 Reply has a ToTag. > > > > A re-initiates the call with a larger session timer, that INVITE has NO > > ToTag - new transaction. The Calls succeeds. > > > > Now I repeat the same, but I send a 181 message back to A BEFORE A > > receives the 422 from C. That 181 has a ToTag. > > > > Now when A re-initiates the INVITE, it includes the ToTag received in > > the 181 and loose_route fails as there is no such transaction. > > > > Is A misbehaving by including a ToTag when it should not? Should the 181 > > reply not contain a ToTag? > > > > I again tried all variants > > > > * sl_send_reply() generates ToTag > > * send_reply() generates ToTag > > * t_reply() does not send the reply. > > > > Mit freundlichen Grüssen > > > > -Benoît Panizzon- > > -- > > I m p r o W a r e A G - Leiter Commerce Kunden > > ______________________________________________________ > > > > Zurlindenstrasse 29 Tel +41 61 826 93 00 > > CH-4133 Pratteln Fax +41 61 826 93 01 > > Schweiz Web http://www.imp.ch > > ______________________________________________________ > > __________________________________________________________ > > Kamailio - Users Mailing List - Non Commercial Discussions -- sr- > > [email protected] > > To unsubscribe send an email to [email protected] > > Important: keep the mailing list in the recipients, do not reply only to the > > sender! __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions -- [email protected] To unsubscribe send an email to [email protected] Important: keep the mailing list in the recipients, do not reply only to the sender!
