Fenestration 41
The Curse of “Free Public Wi-Fi”

Welcome, MyMac readers, to Fenestration – back after a hiatus from the podcast, and now in a written form to reflect our rebrand back to MyMac Magazine. This column is my guide to using your Mac in a world filled with Windows machines. I will cover issues of information exchange with Windows users, using Windows infrastructure with your Mac, and how to run Windows or Windows-compatible software on your Mac.

While traveling back from the US to the UK recently, I was sat waiting in an airport lounge, and I flipped open my MacBook Pro in search of the local WiFi service. What I found was a single service entitled “Free Public Wi-Fi”. Unfortunately, this was not the cut-price gateway to Internet connectivity you might think – and it is all Microsoft’s fault.

You see, when they were building the wireless network stack in Microsoft Windows XP, they configured it so that if it couldn’t find a hotspot to connect to, it would rebroadcast a wireless network ID from the preferred networks list in ad-hoc (computer-to-computer) mode. Now, ad-hoc mode is a pretty pointless feature anyway, because it is much easier to use a flash drive for quick file transfers between computers rather than try and get a wireless network connection going. But, thanks to Microsoft’s even more pointless addition, we see “Free Public Wi-Fi” everywhere – someone connected to a network with that name once, and then turned their laptop on in a public place. XP rebroadcast the network name, and because the name is attractive to other users, they try and connect to it – adding it automatically to their own preferred networks list in the process. In this way, the network name has spread like a virus throughout the computing world.

As a Mac user, it’s pretty annoying, because Apple’s Airport is much more intelligently designed. Microsoft’s design decision with this ‘feature’ is hard to fathom, as it is hard to see circumstances where this behavior might be useful. They have patched XP to stop this behavior, but have never promoted the update or made it available automatically via Windows Update – and even if it is installed by a user, they have to further configure Windows to prevent the rebroadcast behavior.

If you are running 10.5 Leopard, you can spot these networks whatever the name – the Airport menu will have a little icon next to the network name that denotes the network type, and the icon for ad-hoc networks looks like a desktop computer. For users running older versions of OS X, the iStumbler utility allows you to spot these networks and easily avoid them. In short, connecting to an ad-hoc network will gain you nothing, and you can be glad that as Apple users we are not perpetuating the insidious spread of “Free Public Wi-Fi”!


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