Another question from our readers... This one's from 'damngeena' in the forums

Q: Can anyone help me with my network? I have a wireless router with two systems hooked up with wires and 1 computer wireless. Everything works fine. My question is, can I get the network to operate so that when any of these computers are on the internet we only use one IP address? I have a wireless router like I said, but I'm not sure if there are settings where it will only use 1 ip address. I ask this because my cable company charges me 10 extra dollars a month for multiple ip addresses, and I thought that the router fixes this problem. Do I need to worry about this?

A: Good question. Home routers today are pretty much bulletproof; so much so in fact, that the manufacturers don't necessarily bother to educate users on how they actually work anymore. This can lead to some confusion.

Your router does ensure that your entire network only has a single IP address on the Internet. Almost all home routing devices do this, usually through a process called Network Address Translation (NAT).

Since your router is connected directly to your cable (or DSL) modem, it receives the single legitimate IP address given to you by your ISP (you must specifically request multiple IP addresses, though there are some exceptions to this, especially with DSL providers).

The IP addresses that the router provides to your network computers (or that you set yourself) are from the private range of IP addresses and cannot be used to communicate over the Internet.

A router using NAT will gather all outgoing data requests into a 'NAT table' based on the IP address of the network computer that sent the request and the Internet IP address of the computer it is trying to communicate with. For example, say one of your network systems is trying to reach www.pcstats.com. The router will store that computer's IP alongside the IP address of PCstats' web server.

Once this information is stored, the router will forward your data request over the Internet to our web server, but it will change the source address of the data request to its own legitimate Internet IP address as provided by your ISP. When the request reaches our server, it will send data back to the IP address of your router, not the computer that originally requested the data.

Your router will compare the source of the data it just received (our web server's IP address) to it's NAT table. If it finds that a system within your network did request data from our webserver's address, it will forward the data it received from PCstats to the system within your network that requested it, and you will see our website.

This is a very quick explanation of NAT, and I've glossed over some things, but the main point is don't worry; you're covered.