There are several ways to manage web servers and other servers remotely, of which SSH is the most common command line solution. The SSH protocol communicates over an encrypted channel between the server and the client. Like all similar communications, SSH transmits data through a specific port, which by default is the well-known tcp port 22. Since the function of this port is known to many people, it exposes the servers to regular attacks. This is usually avoided - or at least to reduce the number of attempts - by switching this well-known port to another, unknown port number, which can only be detected externally by port scanning, which is a more time-consuming task.
In this write-up, we will look at how to change SSH's well-known TCP port 22 to a unique port number to minimize the number of attack attempts via SSH.

With the help of LAMP systems, we can run dynamic websites on our server or even on our home computer. In this description, we will create a LAMP server on the Debian 11 (Bullseye) operating system, on which the following components will be installed: Apache 2.4.54, MariaDB 10.5.15, PHP 7.4 and phpMyAdmin 5.0.4, UFW firewall.

UCW (Uncomplicated Firewall) is an easy-to-use netfilter firewall management program. It uses a command line interface that consists of a few simple commands and uses iptables for configuration, so it is the frontend of iptables. In this description we will look at the installation and basic use and configuration of the UFW firewall, the steps of which I will perform on a minimal Debian 11 server.

With the help of LAMP systems, we can run dynamic web pages on our server or even on our home computer. I have previously built LAMP servers for Debian 8 (Jessie), Debian 9 (Stretch) and Ubuntu 18.04 LTS (Bionic Beaver), and in this description we will install the LAMP server components for the Ubuntu 20.04 LTS (Focal Fossa) Linux distribution.