(removed sr-dev from CC) Hello, you can do that with the reply_route and/or onreply_route, for an example check out example cfg or this: https://www.kamailio.org/docs/modules/devel/modules/tm.html#tm.f.t_on_reply Cheers, Henning -- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.com<https://gilawa.com/> From: HimaBindu G &lt;himabindu.garadareddy(a)gmail.com&gt; Sent: Tuesday, January 24, 2023 3:16 PM To: sr-users(a)lists.kamailio.org; sr-dev(a)lists.kamailio.org Subject: [sr-dev] Is there any Function or parameter to check Initial Invite Response on Kamailio Hi All, Can you please suggest any function or parameter to check Initial Invite Response from the backend. Thanks & Regards, Hima Bindu.