Hi,

Does the ACK has the correct Router headers and R-URI? Maybe you can share the 200 OK and the ACK headers..

I had a similar issue 3 weeks ago.

Cheers, Francisco.

From: sr-users [mailto:sr-users-bounces@lists.sip-router.org] On Behalf Of Oliver Roth
Sent: 29 June 2016 15:55
To: sr-users@lists.sip-router.org
Subject: [SR-Users] ACK / BYE transaction problem

Hi all

Follow scenario

Class5 system [c5] à Loadbalancer kamailio (dispatcher module) [lbl] -à gateway kamailio [gw] à carrier [carr]

I get Invites from [c5] with

Request ,To, from, contact, pid in national format 0794445566

[lbl] dispatches this to [gw]

For the [carr] I need international format.

So doing these transactions in [gw]

And sending to [carr] in international format

Request, to, from, contact, … => 417794445566

Everything ok

Then I get a 100, 183 and even 200 from [carr]

Ack is coming from [c5] to [lbl] and [gw] – but then it stocks

The ACK is not sent to the [carr]

I kamailio log I see

DEBUG: RFC3261 transaction matching failed

DEBUG: t_lookup_request: no transaction found

So for me, the ACK cannot be assigned to a transaction and gets discarded by

if ( is_method("ACK") ) {

                                                               xlog(,"L_INFO", "WITHINDLG ACK - not loose route\n");

                                                               if ( t_check_trans() ) {

                                                                               xlog(,"L_INFO", "WITHINDLG ACK - t_check_trans() \n");             

                                                                               # no loose-route, but stateful ACK;

                                                                               # must be an ACK after a 487

                                                                               # or e.g. 404 from upstream server

                                                                               t_relay();

                                                                               exit;

                                                               } else {

                                                                               xlog(,"L_INFO", "WITHINDLG ACK - not t_check_trans() DISCARD!!\n");

                                                                               # ACK without matching transaction ... ignore and discard

                                                                               route(NATMANAGE);

                                                                               #t_relay();

                                                                               #exit;

Any idea?

Problem with modifying the sip tags? Or problem with the dialog?

Thanks for helping

OIi