Hello all, I've seen the matter of NAT traversal come up several times, but very few people go into detail about some of the specific problems and how/why they happen. So today I spent a few hours doing a write up of an on-going problem we've had with the Cisco 7940 phones, and a variety of routers. This article goes into quite a bit of detail, giving a breakdown of some of the specific problems we were having, and some of the ways you can resolve it. Although not strictly FreeSWITCH related (despite the FS reference), I'm hoping that this write up will help others understand some of the NAT traversal problems; http://blog.simplicitymedialtd.co.uk/476/analysis-of-cisco-7940-sip-alg-and-... Thanks Cal