Sharing an Internet connection
Extra IPs — buying and building your network
What deep pockets you have! But at least this buys you simplicity. Take a gander:

Note: Instead of a hub, you can use a wireless access point with corresponding wireless network cards (NICs) to connect your computers without cables.
To achieve this simple setup, you must first call your cable/DSL company. You already pay for a single IP address for your primary computer, so request an extra IP address only for each extra computer. If they don’t offer extra IPs or the monthly cost is too high, go back and choose another sharing option. Otherwise, place an order and ask them when your new IP address(es) will be activated.
Then start shopping. For the first item, you actually have the choice between a hub and a switch. They perform identical functions, but switches run more efficiently and cost a little more. If you have just two or three comptuers, It’s probably worth the saved cash to stick to a hub like the Linksys EFAH05W. If you have 4+ computers, consider a switch like the Linksys EZXS55W.
Once you've made that decision, you need to make sure you have one NIC for each computer. You can check by looking for an RJ45 jack (it looks like an enlarged phone jack) on the back of each computer. Those that lack the jack will need an NIC. Internal models like the Linksys LNE100TX are cheapest. If you don’t want to crack open the case, try the USB200M, which simply plugs into a USB port on your computer. For laptops, consider PC card models like the wired PCM200 or the wireless WPC54G (requires wireless access point).
Note: When buying wireless products, you must consider the three competing standards: B (low-speed), G (hi-speed), and A (hi-speed). B and G products are compatible, but both are incompatible with A products.
The last item on the list is cabling. Even if you go wireless, you’ll still need a cable in between the cable/DSL modem and the hub/switch. Wired networkers will also need one cable per computer (as illustrated above). You may have enough cables lying around the house. If not, check out the cable guide to learn about Cat5 and find the right stuff for your setup.
(When you start searching for these products, try PriceGrabber. It’s a nice, clean, easy-to-use price comparison service that will help you find the best deals available.)
When you have all the equipment, set it up—install the NICs, and use the diagram above to connect the cabling. Note that you cannot connect any computer to the port adjacent to the uplink port. Also note that you’re hungry. So have a snack and come back to finish up!