What is this tool for?

You may find yourself in a situation where you need to quickly see if 2 subnets will overlap (or more), for example when peering a VPC/VPC or VNET/VNET.

The following will easily do this for you, see; https://github.com/fgiuba/ipconflict

Installation process

Firstly, you will need to install Python: https://www.python.org/downloads/

Once downloaded, follow the steps to installing and hold off on rebooting.

Now download Microsoft C++ Build Tools: https://visualstudio.microsoft.com/visual-cpp-build-tools/

You will also want to install Windows SDK and C++ x64/x86 build tools, like below.

Restart your system.

If you are on Windows, open up Terminal and use PowerShell or CMD - it should not matter, one might be more granular with output than the other.

You will need to install the Pip tool using: pip install ipconflict

Once installed, you can then use ipconflict ip1 ip2 to display any conflicts (overlaps) like below:

You can find more commands @ https://github.com/fgiuba/ipconflict

Summary

Hope this helps!