do you code registrar by yourself? i use next scheme Sip Agent1 ---- Registrar/Proxy ---- Sip Agent 2 i write the Registrar/Proxy by myself and time by time send ACK to the Agent1 and Agent 2 after their regustered, also i set register requests time on Agent 1 and Agent 2 by my Registrar/Proxy in the response to theirs Register methods For me it's work But if you use third party Registrar then it needs to look deep in it configuration, also after registering you can use p2p scheme and send ACK by it -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20090519/71df176f/attachment.html>