[Asterisk-Users] Multiple IAX clients behind a firewall

[Rich Adamson]

Tim Panton wrote:
> 
> On 13 Mar 2006, at 05:54, Adrian Carter wrote:
> 
>> Hi all,
>>    I've searched the wiki, and my basic assumption at this point is to 
>> run multiple IAX clients behind NAT I need to specifically code each 
>> client to use a different port and then setup that port to be 
>> forwarded from the NAT router to their private IP address.
>>
>>    At the moment, I can't seem to get more than one IAX client 
>> registered behind NAT... am I correct in my above assumption or have I 
>> missed something ?
> 
> No, asterisk's iax treats the combination of apparent-ip-address and 
> port as unique.
> So in fact you do best to turn off any port forwarding. That way your 
> NAT device will allocate
> different ports for each client, sharing the same IP address.
> 
> This works because IAX re-registers (or qualifies) the connection every 
> 60 seconds, which is enough
> to keep the mapping in most NATing router's caches.

There is a known exception to that, and it relates to broken Port 
Address Translation (PAT) code in some cheap firewalls. If the OP 
follows your response and still has a problem, he should consider trying 
another firewall/nat-box/firmware-release.