How to Check Firewall Status in Debian Linux

What is a Linux Firewall and How Does It Work?

A Linux firewall is a security system that controls the incoming and outgoing network traffic based on predetermined rules. It is designed to protect a Linux system from unauthorized access or attacks from the Internet or other networks.

The Linux firewall works by evaluating incoming and outgoing network traffic against a set of rules. These rules can specify which types of traffic are allowed or denied, based on factors such as the source or destination IP address, port number, or protocol. When a packet of network traffic arrives at the firewall, it compares the packet against the rules and either allows or denies it based on the results of the evaluation.

Linux firewall rules are typically stored in a configuration file and can be managed using a command-line utility or a graphical user interface. There are several firewall utilities available for Linux, including iptables, ufw, and firewalld.

Overall, the Linux firewall is an important security feature that helps protect a Linux system from external threats. It is an essential part of any Linux system’s security strategy and should be carefully configured to ensure maximum protection.

How to Check Firewall Status in Debian Linux

To check the firewall status on a Debian Linux system, you can use the ufw (Uncomplicated Firewall) utility. Here are the steps:

1. Open a terminal window and log in as the root user or use sudo to run the following commands as root.
2. Check the status of the firewall using the following command:

ufw status

This will show you the current status of the firewall, including whether it is enabled or disabled and which rules are currently in place.

For example, if the firewall is enabled and has no rules configured, the output will look something like this:

Status: active

If the firewall has rules configured, the output will list the rules and indicate whether they are allowed or denied. For example:

Status: active

To                         Action      From
--                         ------      ----
22/tcp                     ALLOW       Anywhere
80/tcp                     ALLOW       Anywhere
443/tcp                    ALLOW       Anywhere
22/tcp (v6)                ALLOW       Anywhere (v6)
80/tcp (v6)                ALLOW       Anywhere (v6)
443/tcp (v6)               ALLOW       Anywhere (v6)

3. If the firewall is disabled, you can enable it using the following command:

ufw enable

4. You can verify that the firewall has been enabled by checking its status again using the ufw status command.

So that is how to check the firewall status on a Debian Linux system using the ufw utility.

Note: If the ufw utility is not installed on your system, you can install it using the following command:

apt-get install ufw