ZeroTier’s software is open source and free to use for most purposes including personal use, internal use within a business or academic institution, and evaluation for uses that require commercial licensing.
This is a great guide to iptables:
You can generate a self-signed certificate online here:
This will generate a two files – a certificate and a key.
If you are using IIS server you need to convert these to .pfx. For this you can use the SSL Converter here: