This is a guide for using the certbot tool. certbot will allow you to enable HTTPS in a simple way.
To enable HTTPS you will need :
In this guide we will use nginx as our server.
To install certbot run the following script :
sudo apt-get update
sudo apt-get install certbot
sudo apt-get install python3-certbot-nginx
The certbot website will recomend you to use snap but this is not necesarry.
To use certbot you just need to do
sudo certbot --nginx
and follow the instructions.
To add a subdomain (www, mail, …) you will need to use the -d (domains) option and the --expand option.
So to add the subdomains you do the following
sudo certbot -d (Comma-separated list of domains all your domains) --expand
Example with the domain example.org:
sudo certbot -d example.org,www.example.org,sub.example.org --expand