Using SSH on campus with X-Forwarding


Using SSH on campus with X-Forwarding

1) have *nix box set up somewhere you can access it (like, on the internet).
2) get X and sshd running and accepting connections
	(edit /etc/ssh/sshd_config to include the line 'X11Forwarding yes')
	(if you have nmap available, log in to your server and do 'nmap localhost' to 
prove that X is accepting connections from localhost - port 6000 should be 
open. Note: with X11 forwarding over SSH, the X connection actually originates 
from localhost, not from whereever you ssh in from).

3) If there is a firewall in the way, open port 22 (tcp) to the server (port 
6000 does NOT need to be opened).
	(Linksys NAT/gateway/routers - open the web config interface, hit Advanced, 
Forwarding, and add an entry for port 22, tcp, to the address of your server. If 
you're using the DHCP feature, this will be a bit fruity because you have to put 
in the local address of your server, which may some day be reassigned. Tough- 
this router doesn't allow address reservations).

4) Leave. Go to computing commons. Or ECG. Take a laptop and a WLAN card. Get a 
donut.

5) Depending on what hardware/OS you're client is, there are some different ways 
to go here.

No matter which way you do it, you should start up your client-side X-Server 
first. For a Windows box, use Exceed (pre-installed in the labs, or get it @ 
www.asu.edu/it). Under the Exceed folder in the Start Menu just run the main 
'Exceed' entry- no configuration necessary. SSH will figure it out, so to speak.

a) Windows box (ECG, Goldwater, CC, etc) using sshclient
	Start, Run..., type 'sshclient' and Enter. You will have to create a new 
profile to set this up- just check the X11 Forwarding box, enter your IP (and 
any cipher/hashing algorithm preferences you may have - use ssh2!!). You may 
want to delete the profile when you're done, unless for some insane reason 
you're using this ssh client on your own machine... use PuTTY, foo!

b) Windows box using PuTTY (SSH/Telnet/RSH client)
	Enter the IP address, select SSH. If you think you might want to do this again 
someday from the same machine, give the session a name in the 'Saved Session' 
box. Go to the SSH/Tunnels category and check 'Enable X11 Forwarding'. Go back 
to the Session category and hit Save, then hit Open.

You get the idea. Start your client-side X Server (Exceed for Windows, XFree86 
for *nix, something else for Mac), ssh into your server box with X11 Forwarding 
on. Just type in the name of the program you want to use (OpenOffice launches 
with the command "~/OpenOffice/soffice", for example, or "nessus" to launch the 
Nessus vulnerability scanner front-end). If you really want a slow time, launch 
KDE/Gnome first, then use that to launch your apps. Otherwise, just run your 
apps straight from the command line. Regardless, unless the machine you're 
connecting to is on the same network (dorm, etc) it won't be fast. xclock runs 
nicely, though.

Good Luck!


X-Forwarding HOWTO written by Jake Maul (Norman.Maul@asu.edu)


Related Links
-------------
Remote X Apps mini-HOWTO (does not use SSH - this sets up a direct (unsecured) 
link to an X-Server)
http://www.tldp.org/HOWTO/mini/Remote-X-Apps.html

PuTTY
http://www.chiark.greenend.org.uk/~sgtatham/putty/

This HOWTO
http://www.public.asu.edu/~nmaul/x-forwarding.html