(This is Part 3 of a four-part tutorial. Here's a link to the introduction.)
Step 4: Configure Firefox to use the Putty SSH tunnel as a SOCKS proxy
Configuring Firefox to use this new SSH tunnel is simple. Start Firefox, then select the Tools menu, and then select the Options... menu item. Now click the Advanced icon (on the upper-right of the dialog), and then select the Network tab. This is shown in the next figure:
