[Asterisk-Users] SIP extension outside of IP tables firewall

[Kevin P. Fleming]

Brian Weaver wrote:

> I have an Asterisk PBX on the private lan, which is protected
> from the public Internet with a Linux iptables machine. The
> firwall is it's own seperate box running NAT with SPI.

The only way to make this work well is to run a SIP proxy of some kind 
on the firewall system and tell the SIP client to use that proxy. 
Asterisk providing SIP behind a NAT and/or firewall is very difficult to 
get working. A SIP client behind a NAT, on the other hand, works fine as 
long as the client supports STUN.