If you’re using a network device from Apple (like a Time Capsule or an Airport Extreme), Airport Utility’s Timed Access Control setting is a pretty easy way to configure when the machines on your network are allowed to wirelessly connect to the Internet. For each computer, you can use its unique Wi-Fi MAC (Media Access Control) address to block it from the network pretty much whenever you feel like it, which is a big thing for conscientious parents who want to cut off Internet usage at certain times of day. So let’s go over it, shall we? Note that these instructions assume you’re using Airport Utility version 6.0 under Lion, so if you have a previous iteration of the software, your steps are going to be a little different. The basic idea is the same, but feel free to ask questions in the comments if you’ve got them.
So first, find the MAC address of the machine you want to set up time limits for. An easy way to get this is by going to System Preferences > Network on the computer in question, choosing Wi-Fi from the list on the left, and clicking on the Advanced button. The computer’s MAC address will be under the Wi-Fi tab, labeled as Wi-Fi Address.
If it’s an iOS device you’re looking to block, the number you’ll want for that is the Wi-Fi address listed under Settings > General > About.
Of course it doesn’t make a ton of sense if the device you want to block is your kid’s iPhone. That’s a pretty good way to get a gigantic data bill, if you ask me.
Anyway, after you’ve found that number, open Airport Utility (it’s within Applications > Utilities), choose the wireless device you want to configure, and click on the Edit button.
Then select the Network tab, toggle on Enable Access Control, and click the button labeled “Timed Access Control” to configure the settings.
On the next screen, you’ll click the plus button to add a new wireless client setup. Give it an appropriate description and type in the MAC address we found earlier.
Now’s the fun part—set the Wireless Access Times for when the computer with the MAC address you’ve entered will be allowed to use the wireless network. You can click the plus button underneath that section to keep adding new rules, so you could have a separate schedule for the weekend, for example.
When you’re finished, hit the Save button, and then make sure to click on Update to finish configuring the device. That’s all there is to it, and in my tests, this works pretty darned well. One thing I have noticed, though, is that the cutoff times aren’t always exact—they may fluctuate a bit after the time you’ve set. So if little Johnny gets two extra minutes of playing World of Warcraft, you have been forewarned, right?
Please be aware that if you have very smart kids (or adults, I guess) whom you’re trying to block from Internet access, spoofing a MAC address isn’t all that difficult. So if that’s the situation you’re working with, you might want to consider other options, such as using Parental Controls to lock down the little buttheads. That’ll show ‘em.