[Asterisk-Users] Asterisk, IAX and NAT issue

[Simon J Mudd]

Hi Dan,

dtoma at fx.ro ("Dan") writes:

> > Is your firewall redirecting incoming connections on n.n.n.n:5036 to
> > the Internal Asterisk instance?  If you don't see any messages on the
> > inside Asterisk box it's unlikely.
>
> More than that... Asterisk is configured as DMZ in the NAT router, so it is
> fully exposed to the internet.
> More, from outside I can register a SIP phone to the internal Asterisk and
> use it for placing calls.
> 
> > The best thing to do is probably do a tcpdump -n -i eth0 host n.n.n.n
> > and host x.y.z.u (or similar) and try and diagnose what is actually
> > being sent over the wire.
> 
> This is what I get on the internal PBX when trying to remotely connect using
> IAX protocol, by dialing extension 103.
> 
> 16:17:29.382604 193.221.214.29.5036 > 192.168.33.99.5036: udp 121 (DF) [tos
> 0x10]
> 16:17:29.395536 192.168.33.99.5036 > 193.221.214.29.5036: udp 12 (DF) [tos
> 0x10]
> 16:17:29.396791 192.168.33.99.5036 > 193.221.214.29.5036: udp 30 (DF) [tos
> 0x10]
> 16:17:29.682915 193.221.214.29.5036 > 192.168.33.99.5036: udp 12 (DF) [tos
> 0x10]
> 
> 192.168.33.99 is the PBX behind NAT
> 1933.221.214.29 is the PBX directly connected to the Internet
> 
> so the packets goes to the right place, but then...nothing.

I guess you therefore need to check with netstat -ln | grep udp to
check that there is actually something listening on port 5036.  I
don't remember now whether you said if your machine is multihomed
or not, or whether you have any ip filters enabled. Perhaps you are
filtering incoming traffic or something like that.

Sorry I don't have any other suggestions.

Simon