Some readers are reluctant to upgrade or replace vulnerable Windows 7 PCs, even though Microsoft no longer provides security updates for them.
Instead, the readers are searching for technical tricks that would allow them to keep using the Windows 7 PCs while isolating them from other computers on a network. While that sounds good, it's not practical.
Last week, Michael Kehoe of Minneapolis asked how he could isolate a vulnerable Windows 7 PC on his home network (see tinyurl.com/y5on8xko). I said that it was possible to do that (using a Wi-Fi network technology called a subnet), but that it was technically challenging for consumers.
But reader Bill Fuhrmann of Brooklyn Park suggested another way Kehoe might isolate his Windows 7 PC on a home Wi-Fi network. Rather than set up a subnet, Fuhrmann said, why not put the Windows 7 PC on a secondary "guest Wi-Fi network," a feature provided with some newer wireless routers (see tinyurl.com/y4ahn44a and tinyurl.com/y5g6on2s).
Such routers simultaneously run two Wi-Fi networks, one for your personal use and the other for your guests. Supposedly, these two networks can never connect to each other. So, if you let friends use the guest network, any malware lurking on their phones or computers can't infect the computers on your personal Wi-Fi network. Likewise, if you put poorly protected devices — such as some wristband fitness trackers, smartwatches or voice-activated music speakers — on the guest network, their security flaws can't imperil your personal network.
But what if the guest and personal networks really aren't separate from each other? Some researchers claim that it's possible for hackers to first take over your guest Wi-Fi network, then use that foothold to steal data from your personal network by using "cross-router data leaks" (see tinyurl.com/y4cyw94r CQ)..
The researchers said the best solution is to use separate wireless routers for personal and guest networks. But that would add cost and complexity of running a guest Wi-Fi network.
My opinion: Windows 7 isn't safe for consumers to use, and simple Wi-Fi networking tricks aren't likely to make up for that. If you have a Windows 7 PC, upgrade or replace it.