[tlug] Remote desktop viewer not connecting

[Dave M G <dave@example.com>]

TLUG,

I use Ubuntu's Remote Desktop viewer to collaborate with other people on
projects. My computer is the server, the other person's computer is
connecting to me. We are both using Ubuntu. I use the "Remote Desktop"
application in the System->Settings menu, and they use the "Remote
Desktop Viewer" to log in.

It's been working fine for ages. Years even. However, we haven't
collaborated in a couple months, and then a few days when we tried
hooking up again, my computer seems to be refusing all connections. I've
been testing from my laptop, and I can't log in from there either.

First I checked my router. I have TCP ports 5800-5900 and 5500 mapped to
the server machine.

Next I checked my Firewall (with Firestarter), and I have the same ports
open. I also tried turning off the Firewall entirely to see if that made
a difference, but, predictably, it did not.

Sometimes an error message appears on the client side saying the "Avahi"
daemon is not running. I'm not sure if that means the avahi-daemon needs
to be run on the client or the server, so I installed it on both, and
rebooted both.

Now it just always says "Connection to host xxx.xxx.xxx.xxx was closed."
and nothing else.

I've spent the last few hours reading everything on Ubuntu forums and
other places about dealing with the error message, but mostly it comes
down to instructions on re-installing the software, which I've tried.

I looked in /var/log, but I couldn't determine which of the log files
might be relevant. I poked through a few, but it's hard to find the
needle in a haystack when you aren't sure what the needle looks like.

Anyone have any suggestions of a way I might diagnose this problem?

-- 
Dave M G