#!SUITSSydney University IT Society

If you are running a Mac or Linux, don’t worry, there is still a way to use SSH to get free internet. To access the internet in these operating systems, rather than using a GUI, we will be using the command line SSH client.

For those using Windows, scroll down. There is a tutorial for you guys under this post, or available here: Tunneling Through SIT for Free Internet (Windows).

A default installation of both Mac and Linux will almost certainly include the SSH command line tool, so just boot up your computer and we are ready to go. Open up the ‘Terminal’ program. You should see a prompt appear waiting for you to type some commands. We won’t have a pretty GUI to set up our options, so instead we do it using command line switches.

As with most Unix-ish programs, SSH has a pretty standard command line syntax, this is:

ssh [options] [username@]host [command]

Anything in square brackets is optional, we just need to fill in what we need.

As in the windows tutorial what we need to do is create a tunnel to the web server, since it is only inside SIT that unlimited internet exists. To do this, we can take a quick look at the man (manual) page for ssh by typing:

man ssh

We find that we want to create a local tunnel with the -L flag, which has the syntax: [bind_address:]port:host:hostport. Press ‘q’ to exit the man page. Putting all this information together, we now see that the command we will need is:

ssh -L8080:www-cache.usyd.edu.au:8080 unikey@ucpu0.ug.it.usyd.edu.au

What we have done is tunneled the proxy from a computer within SIT, and thus able to benefit from SIT’s free internet, to our laptop.

Finally, all we need to do is tell our computer to connect through the proxy. Set up the proxy settings for your computer to the following:

Proxy: localhost
Port: 8080

For a (very) brief description of how this works, read the “Why…” section of the windows article.