subnetcalc

A simple subnet calculator written in C, statically compiled, and then Dockerized. The Dockerized version was created as a demonstration on how to create really small Docker images from scratch.

Manual build

If you would like to build it yourself, instead of running the pre-compiled image from Docker Hub, simple type make. This will create a image called subnetcalc. If you get a is up to date-message, instead run make --always-make.

Usage

Run it (remove jackbenny/ if you would like to run it from your local build) and enter the subnet mask in slash notation – but without the slash.

For example enter 24 for a 24-bit subnet mask and the program will output the total number of addresses in the range aswell as the total number of usable addresses for hosts.

$> docker run -it --rm jackbenny/subnetcalc
Enter netmask in slash-notation without the slash: 24
Netmask bit: 24

256 total addresses
254 usable addresses for hosts