Reroute all requests through port 80 and other possible ports to authenticated proxy?

Reroute all requests through port 80 and other possible ports to authenticated proxy?

I'm behind the intranet sometimes and have to configure proxy settings manually for a whole slew of applications. I've actually seen some dialog/option with 'Gnome Proxy Settings' and some applications let you specify this. I'm wondering if changing those would globally reroute any requests on * ports to a specified proxy?