[asterisk-users] Terrible, horrible firewall issues in * to * setup

[Lachek Butalek]

My mission is to get one * box to dial another * box' extensions. I
have set this up previously without any issues by making a simple IAX
trunk/extension pair on the two boxes and create a dial plan with a
prefix like 9|XXX to select an extension on the other box.

My problem is that I now have to do this with extremely restrictive
firewalls thrown into the mix - firewalls I have no control over.
Basically, the setup is:

*1 <---> FW1 <---> (Internet) <---> FW2 <---> FW3 <---> *2

I have control over firewall 1 and 3, but not 2. Using port forwarding
(4569 UDP) on FW1, I have been able to make calls from *2 to *1. My
problem lies with making calls the other way, as I have no way of port
forwarding on FW2.

My initial thought was to set up a reverse SSH tunnel from *2 to *1,
which would have worked fine if SSH would tunnel UDP (latency is a
different matter altogether). I found a software called Zebedee
(http://www.winton.org.uk/zebedee/) which claims to do UDP tunneling,
and is able to do it "in reverse", but I can't for the life of me get
it to work.

Before I try further with Zebedee, I thought it wise to ask the *
community if there is a standard solution in this particular case, or
perhaps if I'm attempting the impossible.

Any input is greatly appreciated.