SSH Tunnels How-to?

The_Spider asks: "I periodically browse the net and check web-mail at work, when I have the opportunity. I was wondering if anyone had a nice walkthrough on how to set-up an SSH tunnel. I'm not 100% newbish to Linux but I don't know where to start. (I have a Fedora Core box at home for NAT & DHCP) I'm hoping to combine this for use with portable Firefox. I'm not to worried about security, but I love the notion of taking a portable and encrypted browser with me from place to place. Can Slashdot help?" While this might be a bit FAQ, I figure Slashdot anecdotes on the use of SSH tunnels might be a bit more user-friendly than say, the several task-specific HOWTOs one can find via a Google search. ALso, I'm sure that there are a few of you out there who have discovered interesting ways of using SSH tunnels, not covered by said HOWTOs. So, how are you using SSH tunnels, and can you explain them to those who have not yet discovered the value of their use?

Comments

Just what you are looking for...

[linuxkrn]

Got one of those on my website.

Enjoy http://www.linuxlogin.com/linux/admin/sshtunnels.p hp

Gotta love SSH tunneling

[The Blue Meanie]

I *really* hope my employer doesn't recognize my Slashdot ID. :)

I use an SSH tunnel to forward port 8080 on my desktop machine here at work to port 8080 on my Unix workstation at home that's running an HTTP proxy. I set my Firefox/Mozilla at work to use localhost as its proxy, and I now happily bypass any and all logging and/or site restrictions on my work browsing habits.

I also remote-forward a pseudo-random high port on that remote workstation at home to port 22 on my work desktop machine, giving me the ability to SSH *back in* to work from home, and not monkey with the company's VPN solution that has a client for my home machine that's so buggy it's unreal. That remote SSH call-back also forwards the home machine's IMAP port to the company's Exchange Server so I can read my email over the tunnel, and I port-forward to our network monitoring and backup systems' web interfaces so I can actually do my job.

I guess I can say that my productivity from home would be pretty much zippo if I didn't have SSH tunnels at my disposal.

Re:Gotta love SSH tunneling

[fimbulvetr]

This is exactly what I do, and let me tell you what: It's saved my ass a few times.

I also run two browser profiles with one being the proxied and one being normal, with different shortcuts to each. I separate the instances so my employer still sees a lot of traffic so they don't get suspicious. The work-related ones get me to lots of vendors sites, googling for solutions, etc.

I use a sh script to start my second one. It looks for an already open port just in case I killed the browser accidently and don't need to re-establish the tunnel. It re-establishes if it needs to.

You could also proxy your IM messages through these, though I haven't gone to that length yet. Here's my sh script:

#!/bin/sh

STAT=`netstat -an | grep 8888`;
if [ "$STAT" = "" ];
                then

#friendshomemachine
# ssh -L 8888:127.0.0.1:8888 friendshomemachine "perl -e 'while (1) { print localtime."\n";sleep 10;}'" &
#mine
                ssh -L 8888:127.0.0.1:8888 myhomemachine "perl -e 'while (1) { print localtime."\n";sleep 10;}'" &
#friendshomemachine
# ssh -c blowfish-cbc -C -f -N -L 8888:127.0.0.1:8888 friendshomemachine "perl -e 'while (1) { print localtime."\n";sleep 10;}'" &
#mward
# ssh -c blowfish-cbc -C -f -N -L 8888:127.0.0.1:8888 friendshomemachine "perl -e 'while (1) { print localtime."\n";sleep 10;}'" &

fi /usr/local/firefox/firefox -P encrypted

I've heard blowfish is slower, but it doesn't seem to be when you're just browsing. Feel free to experiment. Others with more knowledge as to what's faster, please let me know.