Monitoring Your Network for Unauthorized Computers

Most modern routers give you the ability to look at logs in order to determine if your wireless network is being used by someone who is not authorized. Many routers will also give you the ability to block unauthorized computers by its MAC Address. The MAC Address of computers will be logged when the devices connect to the wireless router.

Monitoring Logs and Restricting Access on an AirPort Router

To check the logs on an AirPort router for unauthorized devices, open the AirPort Utility and click Manual Setup. After authenticating with your AirPort password, select Advanced > Logs and Statistics.

You should now see the logs. Each time a computer connects, its IP Address and MAC Address are recorded in this area, but you can also see the currently connected computers by selecting Advanced > Logs and Statistics > DHCP Clients.

If you see an unauthorized computer, you can block it by getting the MAC Address from the logs or the currently connected clients. Then open AirPort > Access Control and select “Timed Access” from the drop-down menu labeled MAC Address Access Control.

From the Timed Access view, click the plus button to add a new blocked client. In the resulting drop-down panel, type in the MAC Address you found in the logs, add a description, then in the time limit area set "Everyday" to “No Access.” Select Done when you are finished configuring this window.

You can also change this section to only allow approved computers by selecting the (default) Wireless MAC Address and clicking the edit button.

Under the network time limit, select "No Access," then click Done. Then add the MAC addresses of the computers you with to use on the network using the plus button, and selecting "Everyday - All Day" from the time limit.

When you are finished adding computers to the MAC Address control list, press the Update button in the lower right-hand corner of the AirPort Utility window to save the settings and restart the router. Now, the blocked computers will no longer have access to your wireless network, even if they have the WPA password we set earlier.

Monitoring Logs and Restricting Access on a Netgear Router

Managing logs on the Netgear router is easier. Just select Logs from underneath the Content Filtering area of the control panel. You can also see the MAC/IP Addresses of the currently connected devices by clicking Attached Devices under Maintenance.

To setup a Wireless Access List, click the Setup Access List button from the Wireless Settings link under the Advanced list.

From the resulting page, select click the box labeled “Turn Access Control On,” then click Apply. After the router updates the settings, you will be returned to the same access control list page.

This list works by adding the allowed devices. To add an allowed MAC Address, click the add button. The add page will ask for a Device Name and a MAC Address to add. You can get the MAC address for the connected devices from the Attached Devices list.

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