How to configure the UFW firewall to protect a server in Linux?

The UFW utility is a simple and straightforward interface for managing network packet filtering using the classic iptables firewall. By default, this tool is disabled in many Linux distributions, so before starting the configuration, you need to check its current status and make sure the package is present in the system.

The basic principle of working with UFW is setting a strict default security policy. It is recommended to completely deny all incoming connections and allow all outgoing traffic to minimize the potential attack surface from malicious actors on the network.

Before enabling the firewall, it is crucial to explicitly allow necessary network ports, such as the SSH remote access port, otherwise you will completely lose control of the remote server. Adding permissive rules is performed by specifying port numbers or standard service names from the configuration database.

After adding all necessary rules, the firewall is activated with a single command, and its current status can be viewed at any time using a special verbosity key. This allows you to effectively control the network security of the operating system without deeply diving into the syntax of low-level routing tables.