Kamailio doesn't keep dialog state by default, and wouldn't know that. However, if you use the dialog module... http://kamailio.org/docs/modules/4.3.x/modules/dialog.html#idp3761104‎ -- Alex Balashov | Principal | Evariste Systems LLC 1447 Peachtree Street NE, Suite 700 Atlanta, GA 30309 United States Tel: +1-800-250-5920 (toll-free) / +1-678-954-0671 (direct) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/ Sent from my BlackBerry.   Original Message   From: jaflong jaflong Sent: Friday, March 11, 2016 07:36 To: Kamailio (SER) - Users Mailing List Reply To: Kamailio (SER) - Users Mailing List Subject: [SR-Users] ACK validation Hi When I receive a ACK how do I check that it belongs to a current dialog. Is there a function that will do this _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users(a)lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users