Option for a "local mirror"?

[Marko Käning]

> or set up your local network to force traffic through squid (so you don't need to configure anything on the individual hosts). I know of a bunch of people who've used squid + wccp specifically to make softwareupdate not have to re-download large updates multiple times over a somewhat-slow link.

I've installed squid3 by now.

How do I now tell my several parallel macports installations to use this proxy instead of directly accessing the internet?