[SOLVED] ssh with port mapping for X11 forwarding to bypass router

lleb · 04-24-2012, 07:37 AM

was reading an article the other day about some of the powerful tools of SSH, thus my other thread about sshfs. while reading i was reminded that you can bind a port and use that port for X11 forwarding even if the router is not configured for it.

I have completely forgotten how this works and when I tried I failed to get X11 to forward even when configured properly.

exact from article.

Code:

SSH tip #2: SSH tunnel for road warriors

When you're at the mercy of hotel and coffee shop Internet, a nice secure SSH tunnel makes your online adventures safer. To make this work you need a server that you control to act as a central node for escaping from hotspot follies. I have a server set up at home to accept remote SSH logins, and then use an SSH tunnel to route traffic through it. This is useful for a lot of different tasks. For example I can use my normal email client to send email, instead of hassling with Web mail or changing SMTP server configuration, and all traffic between my laptop and home server is encrypted. First create the tunnel to your personal server:


carla@hotel:~$ ssh -f carla@homeserver.com -L 9999:homeserver.com:25 -N
This binds port 9999 on your mobile machine to port 25 on your remote server. The remote port must be whatever you've configured your server to listen on. Then configure your mail client to use localhost:9999 as the SMTP server and you're in business. I use Kmail, which lets me configure multiple SMTP server accounts and then choose which one I want to use when I send messages, or simply change the default with a mouse click. You can adapt this for any kind of service that you normally use from your home base, and need access to when you're on the road.

the port -L 9999 in this example is used for his e-mail, but cant I do something similar for X11 forwarding, and if so do I need to edit the xorg.conf to listen on that new port?

Thanks in advance for the feedback and guidance.

acid_kewpie · 04-24-2012, 07:52 AM

you don't do that for X11, as X11 forwarding is built in to SSH directly, with the -X (or -Y) option. There's no need to forward any ports at all.

lleb · 04-24-2012, 07:57 AM

howto configure putty to forward X11. sadly our servers use scoansi with some other nasty configuration settings for the user profile (dont ask to long a story) so we putty over. i run FC15 as my desktop and have yet to be successful getting my putty to perform X11 forwarding.

any suggestions around this?

acid_kewpie · 04-24-2012, 08:05 AM

I don't really understand the situation TBH, PuTTY has options to forward X11, so if the character set is something screwing that up, I don't have experience in that area to comment.

lleb · 04-24-2012, 08:11 AM

ahh found some X11 forwarding, what should I put for the x display location? 0:0 or localhost, sorry im more then blonde this morning.

acid_kewpie · 04-24-2012, 08:18 AM

if your genuninely forwarding then it should sort it out for you. This is PuTTY on Linux right? As I read it you have to use PuTTY becuase of the weird SCO ANSI mapping?

lleb · 04-24-2012, 08:18 AM

nm, ignore my last post, problem solved. turns out the server we use to get to our clients is not configured for X11 forwarding and I dont have root access to enable it. Sorry to bother you.