[Asterisk-Users] asterisk + OH323 + NAT + gnomemeeting

[Jesse Guardiani]

Hello,

I've been working a lot with asterisk lately. I've
had a LOT of positive experience with various SIP
clients (grandstream hardware phones & ATAs, X-Lite,
SJPhone, etc...), and I've had no trouble getting
asterisk behind a NAT to talk SIP to clients across
the internet behind another NAT using STUN to traverse
firewalls. In fact, I got to the point that I could
take a hardware phone to just about any internet
connected location, plug it in, turn it on, and have
perfect connectivity (depending on internet connection
quality, of course).

But one of the difficulties I've had is in finding
a good client for Linux. You know, there's the whole
OSS vs ALSA vs arts vs esd issue. X-Lite under Wine
isn't an option because the voice quality is way to
delayed, and X-Lite under Wine crashes on my machine
way too often. So recently I've standardized on ALSA,
because ALSA + DMIX + DSNOOP + ASYM allows me to
completely do away with my sound daemon(s) and do
all of my sound mixing in kernel (sound quality is
a bit worse than with artsd, but more reliable).
However, gnomemeeting seems to be the only VoIP
client capable of working with DMIX + DSNOOP + ASYM
in full duplex!

And guess what? gnomemeeting only speaks H.323 in the
current production version.

So I've compiled the OH323 module and I am using it
with asterisk and trying desperately to get it to the
same plug-and-play level that I had with SIP - and
failing miserably. :(

What appears to be happening is that asterisk's oh323.conf
lacks the "nat=yes" and "externip" and "localnet" config
items found in sip.conf, so firewall traversal doesn't
work nearly as well.

What are my fellow listers doing in this situation?
Running gnugk? Could you share a config with me? Or
perhaps point me in the right direction? Here's my
target network layout currently:

gnomemeeting <-> NAT1 <-> internet <-> NAT2 <-> asterisk

But I need to be able to do this also:

gnomemeeting <-> internet <-> NAT2 <-> asterisk

And also this:

gnomemeeting <-> LAN <-> asterisk

And I need calls to be able to be initiated from both
ends.

NAT2 has TCP/UDP ports 10,000 -> 20,000 pointed to the
asterisk machine, as well as TCP ports 5060, 1720, and
1721. NAT1 *must not* have port forwardings in place
for RTP or H.323, as I don't necessarily have
administrative access to it. In the first diagram, above,
both gnomemeeting and asterisk have private IPs. In the
second diagram above, asterisk has a private IP and
gnomemeeting has a public IP. In the third diagram, there
is no NAT and both asterisk and gnomemeeting have private
IPs on the same LAN.

Any ideas? Will gnugk + asterisk allow me to make this
work? How? Thanks!

-- 
Jesse Guardiani, Systems Administrator
WingNET Internet Services,
P.O. Box 2605 // Cleveland, TN 37320-2605
423-559-LINK (v)  423-559-5145 (f)
http://www.wingnet.net