The objective of Certbot, Let's Encrypt, and the ACME (Automated
Certificate Management Environment) protocol is to make it possible
to set up an HTTPS server and have it automatically obtain a
browser-trusted certificate, without any human intervention. This is
accomplished by running a certificate management agent on the web
This agent is used to:
Automatically prove to the Let's Encrypt CA that you control the website
Obtain a browser-trusted certificate and set it up on your web server
Keep track of when your certificate is going to expire, and renew it
Help you revoke the certificate if that ever becomes necessary.
For versions of Ubuntu between 14.04 LTS (Trusty Tahr) and 15.10 (Wily Werewolf), as well as Ubuntu flavours that don’t include snap by default, snap can be installed from the Ubuntu Software Centre by searching for snapd.
Alternatively, snapd can be installed from the command line:
sudo apt update
sudo apt install snapd
Either log out and back in again, or restart your system, to ensure snap’s paths are updated correctly.
To install certbot, simply use the following command: