I have set up an OpenSER to run on port 5062 instead of 5060. Attached to OpenSER I have 2 videoconferencing clients which communicate via SIP. What's working so far - internal client (registered on OpenSER) to another internal client (registered on OpenSER) - internal client (registered on OpenSER) to another external client - this all works with the OpenSER and other clients behind their NAT, as Mediaproxy is installed What is actually not working is - another external client connetcing to an internal client (registered on OpenSER) because I have to adress the the To:URI as sip.mydomain.com:5062. - Whenever an external INVITE comed in, it ends up with "message too big" because OpenSER is cycling through its routing plan until it adds that many via headers that the message increases 2kb. - what I see is that openser does not try to find the client on sip.mydomain.com, instead I feel that it tries to find the client on sip.mydomain.com:5062 as uri. - as my operating system (debian etch) cannot resolve this domain, this runs through the loop My question: - is the a way to modify the destinaton header ($tu) that the port is cut off (name@sip.mydomain.com:5062 ==> name(a)sip.mydomain.com)? Best regards peter