*NIX commandline subnet calculator

The other day, I was wondering how I could calculate a wildcard subnet mask form a regular netmask of 255.255.255.248. Of course, the answer is 0.0.0.7, but it took me some time to figure it out since I don’t use wildcard netmasks a lot.

During my quest for the right wildcard netmask, I ran into a nice little program you can use under Linux, BSD and the like. It’s called ipcalc and it can be found here: http://jodies.de/ipcalc-archive/ or via the package manager of your choice.