The MAC (Media Access Control) address
is the physical address of a network adapter. This is unique to each
adapter, so you can enhance security by setting up your AP to use MAC
address filtering. This feature means that the AP only accepts
connections from a list of MAC addresses that you specify. If a hacker
tries to connect to your network using a NIC that has a MAC address not
on the list, the AP denies the connection.
Unfortunately, MAC
address filtering isn’t a particularly robust form of security. The
problem is that wireless network packets use a nonencrypted header that
includes the MAC address of the device sending the packet! So any
reasonably sophisticated cracker can sniff your network packets,
determine the MAC address of one of your wireless devices, and then use
special software to spoof that address so that the AP thinks the
hacker’s packets are coming from an authorized device.
Does this mean
you shouldn’t bother configuring a MAC address filter? Not at all. For
one thing, even if a savvy wardriver can fool your wireless AP into
thinking his device is authorized, the hacker still has to get past your
other security layers. For another, not every cracker out there uses
sophisticated tools, such as packet sniffers and MAC address spoofing
software, so your filter will at least thwart those would-be intruders.
Access your router’s setup pages, locate the Mac address filtering section (see Figure 1), turn on Mac address filtering, and then specify the MAC addresses that you want to allow on your network.
Getting the MAC Address of Your Wireless NIC
The good news about MAC
address filtering is that most modern APs come with a feature that
displays a list of the devices currently connected to the AP and enables
you to quickly add the MAC addresses of those devices to the AP’s MAC
address filter. Just in case your AP doesn’t come with this feature,
here are the steps to follow in Windows 7 to determine the MAC address
of your wireless NIC:
1. | Click the Network icon in the taskbar’s notification area, and then click Open Network and Sharing Center.
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2. | In
the Network and Sharing Center’s tasks list, click Change Adapter
Settings. Windows 7 displays the Network Connections window.
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3. | Double-click the wireless connection to open the Status dialog box.
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4. | Click Details to open the Network Connection Details dialog box.
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5. | Make a note of the Physical Address value (see Figure 2), which is the same as the MAC address.
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6. | Click Close.
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Note
Another way to find out the MAC address of your wireless network adapter is to select Start, type command, and then select Command Prompt to open a Command Prompt session. Type the following command and press Enter:
Find the data for the wireless adapter and look for the Physical Address value.
Tip
While we’re on the
subject of wireless NICs, this is as good a place as any to talk about
security updates. Wireless NIC vendors occasionally find security
vulnerabilities in their NIC device drivers, and they issue patches and
driver upgrades to fix those security holes. You should check the
manufacturer’s website from time to time to see whether any updates are
available for your NIC.
