How Network Address Translation Works

Computers and devices on the Internet need to have a unique IP address to perform tasks like searching the Web. However, the Internet's boom has left us short of IP addresses. But don't get nervous just yet. We've got back-up.

Since there aren't enough IP addresses, Network Address Translation, or NAT, is used. NAT is performed by a home router in a home network. The router has its own IP address, which is assigned by an Internet Service Provider. And only that IP address is visible on the Internet.

Each PC on the home network gets an internal IP address, but only the router's IP address is used on the Internet.

The router knows each PC's internal IP address, so knows which computer is requesting information and which to direct the incoming infromation.

The benefits of NAT are that it helps keep hackers away since PC's use the router's address to use the Web, not its internal IP address, and that it helps to solve the shortage problem of IP addresses. (Yes, I realize there is IPv6..but later on that.)

For more info, check out http://computer.howstuffworks.com/nat.htm