IMO as a provider, FS does an excellent job at detecting NAT on its own and handling it. We've rarely had any issue with our end sending INVITEs to the wrong place or one / no way speech. connectile dysfunction does nothing more. The only switch we enable is one to enable the SIP options ping and to use sip-force-expires to reduce the time the endpoint re-registers for mobile devices. As with others on this thread, the ALG in most routers is the culprit, I've rarely experienced one which does anything beneficial, most screw up the headers. We also recommend that customers change the SIP port on their handsets to anything other than 5060, older BT routers especially seem to stop forwarding responses after a few minutes, again as they have a very basic ALG. Using port forwarding in the router is the only sure fire way of getting reliable SIP through to a handset, Draytek routers seem to be pretty flaky until you do this or use TCP / TLS. If the router stops forwarding packets because of a poor ALG implementation or other firewall rules, nothing FS can do will overcome this. -- View this message in context: http://freeswitch-users.2379917.n2.nabble.com/NAT-traversal-the-final-say-tp... Sent from the freeswitch-users mailing list archive at Nabble.com.