Hi all, I’m having some issues with ACK’s. Specifically, when an ACK reaches Kamailio from either Asterisk or an endpoint, Kamailio is adding a second Via header - which isn’t valid as per RFC 3261 (17.1.1.3); “The ACK MUST contain a single Via header field, and this MUST be equal to the top Via header field of the original request." Endpoints are registered with Kamailio but INVITES are routed via Asterisk for dial plan and media reasons. I’m running fairly bog-standard Kamailio and Asterisk installs. I’ve attached a sample PCAP for if anyone has any suggestions. Thanks. Dan