[Asterisk-Dev] How IAX workd behind the firewall

[Adam Hart]

twisted wrote:

> On Mon, 2004-07-12 at 04:28, Adam Hart wrote:
> 
>>IAX uses a single port (4569 udp) - firewalls are different to NATs and 
>>IAX's ability to get through is entirely dependent on the firewall 
>>rules. Same goes for SIP although there is 2 ports in that case
>>
>>Shanmuganathan Kumaravel wrote:
>>
>>>Hi there,
>>>
>>>    Can anyone suggest, how IAX works behind the firewall. Also is it possible to do the SIP crossing the firewall.
>>>
>>>Regards
>>>Shan  
>>>
> 
> 
> Actually, with SIP you will need 3 ports.   1 for control (5060) and two for RTP.
> 

That's H.323 I believe, SIP just uses one RTP port as stated in SDP payloads