How to Filter MAC Addresses on Wireless Network

Configure MAC address filtering to improve your wireless network security.

Wireless network security is an important topic in our interconnected world, and rightly so. Wireless networks are not only easy to set up, but they are also easy to hack. Unless you implement several recommended security measures your wireless network will be an easy target for a war-driving hacker or anyone else who hops onto your unsecured network. One of those measures is MAC address filtering, which limits the computers that are allowed to connect to your wireless network.

Difficulty:

Moderately Challenging

Instructions

1. Identify and make a list of the MAC addresses of all computers that need to connect to your network. Click "Start," type "cmd" in the Search Box and press "Enter." This will open a Command Prompt window.

2. Key "ipconfig /all" at the command prompt and press "Enter." This will produce a display of all of the IP information for the network interfaces on your computer.

3. Scroll through the output and find your computer's wireless interface. Note the line that starts with "Physical Address." The MAC address is listed to the right and consists of six pairs of alphanumeric characters. Add this address to your list.

4. Ensure that each computer is able to connect to the network before you build the MAC address filter in your router.

5. Enable MAC address filtering and use your list to build the table of allowed network interface addresses. Each router manufacturer will have its own specific configuration instructions, but each will have options in the administrative menu for enabling MAC filtering and building the table. Enter each address from your list according to the router management software instructions. Some routers may require you to enter the addresses with hyphens and some will require you to enter the addresses without the hyphens. Click the appropriate buttons to save the configuration changes and restart your router if required.

6. Verify that each computer can still connect to the wireless network. If a computer cannot connect, check the MAC address of the computer, verify it against your list and check to be sure you entered it correctly into the router. Correct any errors and retest.

References

• Windows 7 Themes: How to Find the MAC Address in Windows 7
• Small Business Computing; What's a MAC Address and How Do You Find It?; Ronald Pacchiano; March 2011
• Time Atlas: Enabling MAC Filtering
• NetGear Documentation: Restricting Wireless Access by MAC Address
• Columbia University: Linksys WRT54G Setup

Resources

• The Geek Stuff; 6 Steps to Secure Your Home Wireless Network; Ramesh Natarajan; August 2008
• The Unofficial 802.11 Security Web Page
• LanArchitect.net; Wireless LAN Security Guide; George Ou