[Asterisk-Dev] Has anyone got Asterisk working behind a NAT connection to users within a NAT

[Fats Neutron]

I was wondering if anyone has managed to get a working solution with
asterisk behind a NAT connecting to external sip users behind another NAT.

I have been using iax for the asterisk box without any issues including
internal and external connections as well as connecting multiple asterisk
boxes together with shared dial plans.

However, and I know this is a running issues, I cannot get external sip
users behind a NAT to be able to successfully connect to asterisk when it's
behind a NAT as well.

The external sip user correctly registers with asterisk and I can dial their
phone and they can dial into to any phone internal to the network. They can
even hear my conversation when they use an external stun server (in this
case stun.xten.net) but they cannot hear me.

When debugging I realise that the ip addresses are not pointing at the right
internal server and hence the traffic never gets through.

I have been looking at using ser but after compiling and testing it I never
found a solution owing to it's complexity and the possibility that I would
need to get ser to answer calls on port 5060 and potentially redirect them
to another port (say 5061) for the sip phones.

I have done port forwarding at both ends dealing with the usual ports of
5060, 4569 and 5036 as well as opening up the rtp ports for the voice
traffic on 10,000 to 20,000.

Is there a way without asterisk being on an external ip?

Any help would be useful especially if someone has managed to get a working
system.

Thanks or your help.

Regards
Fats

--
Fats Neutron
Fats.neutron at grandmore.com