Secure Knowledge
I believe that there’s a significant error in the “Secure Your Network Devices” article, which appeared in the December 2017 edition. When discussing subnets and VLANS, the author claims that “You can identify which subnet a device belongs to by the first three numbers in your IP address….” That’s only true when the device is configured to use a 24- bit subnet mask ( 255.255.255.0). Granted, that’s probably the most common configuration out there, particularly in small and home offices, but it simply isn’t possible to determine a subnet by looking at the IP address alone.
– Phil Hoffman
EXECUTIVE EDITOR ALAN DEXTER RESPONDS: You’re absolutely right in terms of the bigger picture, but at the same time, this was written in fairly basic terms for anyone trying to secure their home network. And from an internal perspective, this is enough to just know that you’ve set up a device on the right subnet (assuming, of course, that you’ve set up the subnets yourself).