MAC cloning on Airport Extreme

A friend called with Internet connection trouble. He had purchased an Apple Airport Extreme for his Mac, but wasn’t able to get it to connect. Since I’ve done this sort of thing hundreds of times, it sounded like a simple thing to fix.

I did the usual troubleshooting, making sure the wires were connected correctly, choosing the right options in the software. What I noticed after some struggling was that the Airport Extreme doesn’t have the option to clone the MAC address (unique hardware address) of the computer’s Ethernet card, something that is available on all other brands of routers that I have ever seen. Even after searching multiple forums, they all had the same thing to say – no MAC cloning. Some forums even gave people a real attitude about this, as though cloning were something questionable or hackerish. But once a cable modem binds to a MAC address, it won’t vend to another until the modem is reset.

I concluded that the cable modem would have to be reset so that it could bind to the MAC of the Airport. I unplugged the Mac computer from the Airport, and the Airport from the modem. I disconnected the coax cable from the modem (a Motorola Surfboard) and unplugged the power to the modem. I also unplugged power to the Airport router, and waited a few minutes.

I plugged the power back into the Airport. I plugged the ethernet cable back from the Airport to the modem. I then plugged the power back into the modem and let it try in vain to find the cable for a minute. I then reattached the coax cable to the modem so it could re-establish a connection to Comcast. The only device connected to the modem was the Airport router, so the cable modem would bind to its MAC address. After a minute or so, the Airport light turned green, signifying that it was ready. I plugged the Mac computer into a port on the Airport.

On the Mac computer, I had the network setting window open and had it set to DHCP. It updated dynamically to show that it now had a private IP of 10.0.1.4, a good sign that the Airport had given it an IP. I checked the settings on the Airport (though the Airport utility) and it showed that it now had the Comcast IP. All was well. Safari (web browser) was able to connect to websites.

It was more than a bit frustrating that Apple didn’t bother to include the MAC cloning feature in their flagship router. But this procedure allowed me to work around that and bind the Airport’s MAC to the modem.

(I also found the Airport utility one of the more frustrating bits of software I’ve dealt with. Non-intuitive, poorly explained, and badly labeled options.) Also, make sure the Airport is set to “share a public IP”, rather than the other options.

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