Fortunately, one of the best people ever to work on the net has a fairly simple solution. John Norstad, who brought the world Disinfectant, the free and friendly anti-virus program, has created MacTCP Switcher, which lets you save multiple TCP settings and switch between as many of them as you like. It's simple to install, and its own documentation explains the process well. I keep aliases of my configurations available on my Apple menu for quick switching, though you do have to restart every time you change. A brilliant and simple convenience, and it's even freeware.
One small warning - this doesn't change the Hosts file at all. If you put a name into the Hosts file, the Mac will look for that name at the address in the Hosts file rather than in the outside world.
Copyright 1995 by Simon St.Laurent. All rights reserved. You may print this document for yourself or others at no charge, but commercial distribution without permission is prohibited.