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



                                                               } else {

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

                                                                               # ACK without matching transaction ... ignore and discard







Any idea?


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



Thanks for helping