MAC address filtering

MAC address filters are often used as an added wireless security measure next to data encryption. A MAC address (or hardware address or physical address) is a unique code that is assigned to nearly every piece of network equipment. You can use the MAC address to either allow or block a wireless network card that tries to connect to the wireless network.

The MAC address is a 12 charcter hexadecimal code, for example 00-C0-26-A9-42-F7. The Linksys WRT54G allows you to create a list of either blocked or allowed MAC addresses.

  1. Access your router by typing in your webbrowser. Login to the router. If you haven't changed the password yet: the default username and password are both 'admin' (without quotes).
  2. Go to Wireless > Wireless MAC filther and set theWireless MAC Filteroption toenable. 'MAC
  3. You can now choose betweenPreventorPermit only. If you choose Prevent you can specify a list of MAC addresses that are denied access to the wireless network. You than assume that everyone may connect to the wireless network, except for the MAC addresses you specify. Choosing Permit allows you to specify a list of MAC addresses that are permitted to access the network. Using Permit the router's default action is to block a computer, unless it is listed in the MAC address list. In this way you can grant access per computer, which is preferred for non-public networks that allow only trusted computers to use the wireless network.
  4. Choose Permit and in the MAC address list, type the MAC addresses that are permitted to access the wireless network.

How to find the MAC address of your computer's wireless network card? In Windows XP or 2000 go to Start > Run... > type 'cmd' and press enter > type 'ipconfig /all' in the prompt. The MAC address is called "physical address" in Windows and is displayed in the list.

If you read this wireless network security guide from the beginning you now have a wireless network secured with either WEP or WPA encryption and MAC address filtering. This is pretty decent wireless security for a home network, especially if you use WPA encryption, or the even stronger AES encryption.

In the next chapter I will discuss SSID broadcast.