I have Debian and I set it up so that when a VNC connection is made to my computer, it forwards to XDMCP. I did this by modifying the following files as follows:

/etc/services:
vnc-800x600 5900/tcp
vnc-1024x768 5901/tcp
vnc-1152x864 5902/tcp
vnc-1280x1024 5903/tcp

/etc/inetd.conf:
vnc-800x600 stream tcp nowait nobody /usr/bin/Xvnc Xvnc -inetd -query localhost -once -geometry 800x600 -depth 24 securitytypes=none
vnc-1024x768 stream tcp nowait nobody /usr/bin/Xvnc Xvnc -inetd -query localhost -once -geometry 1024x768 -depth 24 securitytypes=none
vnc-1152x864 stream tcp nowait nobody /usr/bin/Xvnc Xvnc -inetd -query localhost -once -geometry 1152x768 -depth 24 securitytypes=none

It works great internally on my home network, but when I try to connect from school using Windows XP Pro and vncviewer.exe, after entering my IP and port, the vncviewer dialog disappears after saying "Attepting to connect to host".

I even tried starting the vncserver on port 80 using (not sure what httpport is compared to basehttpport)

vncserver -depth 24 -geometry 1280x1024 -httpport 80 -basehttpport 80

and when I try to connect with a web browser on port 80, my log file on my computer at home has the following:

17/02/05 19:47:19 Xvnc version 3.3.7 - built Sep 25 2004 21:10:01
17/02/05 19:47:19 Copyright (C) 2002-2003 RealVNC Ltd.
17/02/05 19:47:19 Copyright (C) 1994-2000 AT&T Laboratories Cambridge.
17/02/05 19:47:19 All Rights Reserved.
17/02/05 19:47:19 See http://www.realvnc.com for information on VNC
17/02/05 19:47:19 Desktop name 'X' (chadjohnson:2)
17/02/05 19:47:19 Protocol version supported 3.3
17/02/05 19:47:19 Listening for VNC connections on TCP port 5902
17/02/05 19:47:19 Listening for HTTP connections on TCP port 80
17/02/05 19:47:19 URL http://chadjohnson:80
17/02/05 19:47:46 httpd: get '' for 0.0.0.0
17/02/05 19:47:46 httpd: defaulting to 'index.vnc'
17/02/05 19:47:47 httpd: get 'vncviewer.jar' for 0.0.0.0

and it (the browser) just hangs for a while and then gives me an error message (I post what it says if needed). vncviewer still does not work at this point on port 5902. I configured my hardware firewall so it allows every TCP port I listed in my services file. Is my school's firewall blocking this or something?

I can connect to my computer with putty/SSH just fine.

Why don't you tunnel your vnc session through secure shell? I have had much better luck using this method plus it's mo secure.

I couldn't figure out how to do that. Can you give me an example?

I found this site (http://www.uk.research.att.com/archive/vnc/sshvnc.html), but on the end that I want to run the client, I'm running Windows and I can't just run an ssh command from a shell (maybe I need a 'ssh.exe'?)

Download the ssh client from ssh.com. This client will allow you to tunnel through. Here is what I do. I have vnc start and listen on 127.0.0.1 this way you don't have to worry about people connecting to it from the network. Then I allow ssh through my firewall and start a tunnel from my linux workstation at work. ssh -c blowfish -L 5901:localhost:5901 me@www.me.com. Start vnc enter localhost:1 and I connect to my vncserver. With the ssh.com ssh client it works basically the same but you have to set it up in edit/preferences/tunneling.

Got it. I searched the forum and found out exactly how to do port-forwarding with putty. Sweetness. I didn't think it would work. Thanks for the idea.