[Asterisk-Users] Known SIP - NAT Solutions?

[Matthew Farley]

     I have recently begun experimenting with Asterisk, and have been
mightily impressed by its capabilities and flexibility. I have run
across one problem, however, that challenges my ability to use it as a
production system.

     My Asterisk box has a public Internet IP, and works great with SIP
(ATA 186) clients that also have public IP addresses. Unfortunately,
most of the locations that I would like to put these SIP phones into are
behind NAT. Calls placed from behind NAT are consistantly unsuccessful.
I have read in several places that there are software solutions to this
problem, though I have found no specific references to precisely what
software to use, or how it should be configured to hand these calls off
to Asterisk.

     Has anyone on the list successfully overcome this limitation? If
so, any advice you might be able to provide would be greatly
appreciated.

Thanks!

Sincerely,
Matthew Farley
asterisk at wheatstate.net