How To Harden OpenSSH on Ubuntu 20.04
Linux servers are often administered remotely using SSH by connecting to an OpenSSH server, which is the default SSH server software used within Ubuntu, Debian, CentOS, FreeBSD, and most other Linux/BSD-based systems. In this tutorial, you will harden your Ubuntu 20.04 OpenSSH server by using different configuration options to help ensure that remote access to your server is as secure as possible.