Sipcalc – An advanced IP calculator supporting both IPv4 and IPv6
github.com
github.com
That said, probably maintenance is not needed. I am not aware that anything in that field has changed for a long time.
It's good news for me that this exists on the command line just out of my distro's repo. I don't need such calculations every week. When I did I just did a search and used whatever online tool came up. Sometimes the hits are good, sometimes they are crappy pages full of ads and/or poor functionality. It has also happened (not necessarily related to netmask calculation ) that some random online tool has provided wrong results.
To point out the bleeding obvious, it's not necessarily about the subject matter changing, but the technical environment. Systems change, libraries change with them, leading to potential compilation issues amongst other things.
This is aptly demonstrated by emagii/sipcalc[1], which although no longer maintained itself since 2017 was "sipcalc-1.1.6 updated for cross-compilation, fix warnings".
A quick search on Github eventually reveals troglobit/netcalc[2] as the current maintained clone of sipcalc.
[1]https://github.com/emagii/sipcalc [2]https://github.com/troglobit/netcalc
This project is
* Written in C
* Small
* Built with './configure && make'
Maintenance is almost certainly never going to be needed for this guy. It was done in 2014. Indeed, I just built it on my "bleeding-edge" Gentoo box and it runs just fine.
Normally I’d use the subnet calculator on MXToolbox’s website for convenience but it doesn’t support IPv6.