Hello, I have this scheme: SIP Carrier (external IP 22.203) < > (local ip 1.21) mikrotik < > (local ip 1.21) Kamailio - (local ip 1.15) Asterisk. Carrier does not know what is Route header. that is why Carrier send ACK directly to 1.15 and fail. I change Contact at Kamailio to 1.21 then ACK is coming to Kamailio. But i think it's wrong way... How can i get ACK from CArrier to Kamalio and route it in right way? Thanks