[Asterisk-Users] IAX2 and NATs that increment ports

[Eric Wieling aka ManxPower]

CuPoTKa wrote:
> 
> Eric Wieling aka ManxPower wrote:
> 
>> This is the way NAT works.  It's not a problem for Asterisk unless you 
>> are doing something silly like port forwarding 4569/UDP on your NAT 
>> router.  Asterisk doesn't CARE about the source port of the client.
> 
> 
> Yes... but, doesn't it loose connection? For example, client registers 
> at a.b.c.d:1111, and asterisk thinks that it's there. But after a second 
> it jumps to a.b.c.d:1112 without new registration with asterisk. And it 
> can't speak anymore.
> Client's send registration to asterisk any n00 seconds, but it change 
> it's port any second (or even any new UDP packet?).

That would indicate that your NAT router SUCKS.

You should take your NAT router, put it in the middle of an empty 
parking lot, draw a pentagram around it (have a priest on hand just in 
case), and torch the sucker.

NAT routers are supposed to keep track of active port and address 
translations for UDP and keep the translations active in case there is 
more traffic on that port.

Most NAT routers wait at least 120 seconds before closing UDP 
translations.  IAX2 is a pretty chatty protocol and should not have 
issues with most NAT routers.

You might put qualify=yes in iax2.conf to make the IAX2 connection a bit 
more active to keep the router from closing the NAT translations.