Here's a list of firefox add ons that give alot of control back to the user.
https://addons.mozilla.org/en-US/firefox/addon/59
Yout browser identifies itself to a webserver with each page that it fetches. Sometimes a web server may deny or grant your request based on this useragent string. A site may choose not to "support" a certain browser or it may let googlebot see its pages without logging in.
So I got a nice little acer aspire one, and I've been using the wifi around town. It is really annoying when you get behind a firewall that only lets certain ports out.
I wrote a perl cgi script that will set up iptables port forwarding rules to put a service (like ssh or a vpn) on a non-restricted port (like 443). The rule only affects the IP address from which the cgi was accessed.
of course it has to run as root to set up the iptables rules.
