How to Share an Internet Connection, Part Two
Adapted from Chapter 5 of The Little Network Book, by Lon Poole and John Rizzo, illustrations by John Grimes
This article is provided courtesy of Peachpit Press.
About Internet Gateways
You have a choice between a hardware gateway and a software gateway. If you're using an Ethernet network, you can plug a freestanding hardware gateway into your Ethernet hub, just as you plugged in your computers. Alternatively, you can run software on one of your networked computers to perform the same function as the hardware gateway.
Gateway name game: Internet gateways, both hardware and software, go by various names. Some are called Internet gateways, others are called routers, and still others are called proxy servers. Technically speaking, routers, gateways, and proxy servers are different animals, but manufacturers use the terms loosely. A gateway can contain one or more of these features.
Some gateways direct traffic between your local network and the Internet by translating the private IP address to the one public IP address for outgoing Internet traffic and by routing all information requests from your local network to the Internet using the public IP address. The gateway forwards incoming Internet traffic from your public IP address to the appropriate private IP address of the computer that requested the information.
This process is called network address translation. It's also called IP masquerading, because all of your networked computers masquerade as one computer on the Internet (because they share a public IP address).