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Six Ways To Protect Your Wireless Network: Page 3 of 6

After this, you'll have to set up encryption on each of your PCs, using the same key as you used in the router. In XP, on each PC, click the wireless connection icon in the System Tray and click the Properties button. Click the Wireless Networks tab, highlight your network, click the Properties button, and then click the Association tab. In the "Network Authentication" drop-down box, select your encryption method. In the "Data encryption" dialog box, choose TKIP. Next, uncheck the "The key is provided for me automatically" box. Enter your WPA key in the "Network key" box, and type it again in the "Confirm network key" box. Click OK and then OK again. The PC can now connect to your network using WPA encryption. Step 3 -- Filter Out MAC Addresses

Little-known fact: Every piece of networking hardware has a unique ID number, like a serial number, called a MAC address. No two pieces of networking hardware have the same MAC address. A MAC address looks something like this: 00-08-A1-00-9F-32.

You can use these MAC addresses to keep out intruders. Many routers let you permit only certain MAC addresses onto the Internet. You can tell your router to let in all of your computers, and keep everyone else out.

Again, how you do this varies from manufacturer to manufacturer, and even from model to model. On a Linksys WRT54GX4, log into the administrator screen, and click the Wireless link, and then Wireless Network Access. The Wireless Network Access screen appears, with boxes labeled MAC 1, MAC 2, and so on, up to MAC 50. Select "Permit only PCs listed to access the wireless network. Scroll to the bottom of the screen and click "Select MAC Address from Networked Computers." From the screen that appears, make sure all the boxes are checked, and click Select. You'll be sent back to the Wireless Network Access screen. All the MAC addresses that you check will be automatically filled into the boxes next to MAC 1 and so on. Click Save Settings. Now only PCs on your network can connect to it; all others will be blocked.

What happens if you buy a new computer, and want it to get onto your network, or you have a friend over who wants to use your network? You just need to find their wireless adapter's MAC address and pop it into a MAC box on the Wireless Network Access screen. To find out the network adapter's MAC address, choose Start-->Run, type command, and press Enter. A command line box will open. Type ipconfig /all and press Enter. Look for the numbers next to "Physical Address," such as 00-08-A1-00-9F-32. That's the MAC address. Copy that number into a MAC box on the Wireless Network Access screen, and that computer will be allowed to connect to your network. When you copy the number, don't include the hyphens.