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The Simplicity of UFW Firewall in Ubuntu Linux

Introduction to Firewall and UFW Firewall

Firewalls are an essential tool in securing networks and protecting computer systems from malicious attacks. Many organizations rely on firewalls to safeguard their data while allowing authorized traffic to pass through.

Firewalls act as a barrier between the internet and the network or device they are protecting and evaluate incoming and outgoing traffic based on predefined rules. Firewalls are designed to prevent attackers from accessing a network through vulnerable ports, stopping cyberattacks such as hacking, phishing, and malware.

However, the process of selecting and implementing a firewall can be a daunting and complex task, especially for those with limited technical knowledge. In Ubuntu Linux, there is a user-friendly firewall option known as the Uncomplicated Firewall (UFW) that can help make the setup process more manageable.

In this article, we will provide an overview of firewalls and delve into the UFW firewall, highlighting its features and exploring the steps for installation and activation.

Defining Firewalls and Their Functions

A firewall, in computing terms, is a software or hardware device that filters internet traffic and blocks unauthorized access. It acts as a gatekeeper and provides protection for devices, networks, and applications.

Its main function is to control access by analyzing incoming and outgoing network traffic, usually based on predetermined rules. By filtering traffic, firewalls minimize the risks of malicious traffic that may harm a network system.

Apart from filtering traffic, firewalls offer a range of other functions, including:

1. Packet Filtering: Analyzes packets based on preconfigured rules that determine the types of protocols, ports, and addresses they can access.

Packets that do not comply with the rules are filtered out. 2.

Network Address Translation (NAT): Firewalls can rewrite IP addresses to hide a local network from external networks. This function is useful in preventing hackers from identifying internal IP addresses.

3. VPN Routing: Some firewalls are capable of routing encrypted VPN traffic to a remote network server, ensuring the highest levels of security for communication.

4. Proxy Service: A proxy firewall controls network traffic while hiding the true identity of a device in the network by maintaining a buffer between end-users and the UFW Firewall and Its Features

A UFW firewall is a more straightforward version of a firewall, designed to simplify the installation and management of the firewall system.

UFW is an acronym that stands for Uncomplicated Firewall, and as the name suggests, it is easy to use, has a graphical user interface, and runs on top of the iptables system. One of the key benefits of UFW is that it can be managed and configured without technical expertise.

It provides predefined rules that enable users to control access to their systems with ease. It also includes an easy to use GUI for those who are not comfortable with command-line interfaces.

Some of the features of UFW include:

1. Easy Installation: UFW is pre-installed on Ubuntu, which means there is no need to install additional software or packages.

2. Simplicity: UFW is designed to be user-friendly and to simplify the firewall’s setup and configuration tasks.

3. Integration With The System: UFW works with well with other networking tools like iptables making it compatible with the Ubuntu system.

Installing and Enabling UFW Firewall

The following are the steps required to install UFW firewall on Ubuntu systems:

Step 1: Open the terminal

The first step is to open the terminal on your Ubuntu system. This can be done by pressing the Ctrl + Alt + T keys simultaneously or by selecting the terminal from the applications menu.

Step 2: Install UFW Firewall

Type the command “sudo apt-get install ufw” to start the installation process. Press the enter key, and the software package will be downloaded and installed.

Step 3: Check UFW Status

After the installation is complete, type the command “sudo ufw status” to check the status of the UFW firewall. If UFW is not active, the output will say “inactive.”

Step 4: Enabling UFW Firewall

To enable UFW firewall, type the command “sudo ufw enable.” Hit enter.

This will activate the UFW firewall and turn it on. Step 5: Allow Services

UFW firewall blocks all incoming connections by default.

To allow services like SSH, HTTP, HTTPS, and other services, use the command “sudo ufw allow [service name].” For example, to enable SSH, use the command, “sudo ufw allow ssh.”


Firewalls play a vital role in protecting computer systems and networks from cyberattacks. UFW firewall provides a simpler, easy-to-use option for Ubuntu Linux users, making it an ideal option for those who do not want to deal with the complexity of traditional firewalls.

With the steps outlined above, installing and activating the UFW firewall can be achieved by anyone, even for those without technical expertise.

Configuring UFW Firewall Rules

After installing and enabling UFW firewall on Ubuntu, the next step is setting up the rules. UFW allows the customization of rules according to specific requirements.

The configuration of rules can help in allowing outgoing connections, modifying rules for services, and blocking incoming traffic. This section covers setting up IPv6 and default policies, allowing outgoing connections, modifying rules, deleting rules, and disabling the firewall.

Setting Up IPv6 and Default Policies

IPv6 is the latest version of the Internet Protocol that is designed to replace IPv4. In Ubuntu, the UFW firewall is pre-configured to support IPv4 only.

To enable IPv6 and set default policies, follow the steps below:

Step 1: Check if the System Supports IPv6

Type the command “cat /proc/net/if_inet6” to find out if your system supports IPv6. If the output shows IPv6 addresses, then your system supports it.

Step 2: Enable IPv6 in UFW

To enable IPv6, type the command “sudo nano /etc/default/ufw”. Locate the line “#IPV6=yes” and remove the “#” sign at the beginning of the line to uncomment it, then save the file.

Step 3: Default Policies

Default policies are the rules that determine what to do with incoming and outgoing traffic that doesn’t match any specific rule. The recommended default policies for UFW are:

sudo ufw default deny incoming

sudo ufw default allow outgoing

With these rules, all incoming traffic will be blocked, and outgoing traffic will be allowed. Remember to add rules for specific services that need access.

Allowing Outgoing Connections and Modifying Rules

By default, UFW allows all outgoing connections unless configured otherwise. However, there may be cases where outgoing connections may be blocked.

To allow outgoing connections, follow the steps:

Step 1: Allow Outgoing Connections

Use the command “sudo ufw default allow outgoing” to allow all outgoing connections. Alternatively, to allow outgoing traffic only for specific services, add the relevant rules using the “sudo ufw allow [service name]” command.

For example, to allow SSH traffic, use the command “sudo ufw allow ssh.”

Step 2: Modifying Rules

To modify a rule, use the “sudo ufw allow [port]/[protocol]” command to open a port for incoming traffic. For example, to allow HTTP traffic, enter “sudo ufw allow 80/tcp.” If you wish to delete a previously added rule, use “sudo ufw delete [rule number]” command and enter the number of the rule you want to delete.

Deleting and Disabling Firewall Rules

To delete firewall rules that you no longer need, use the “sudo ufw delete [rule number]” command and enter the number of the rule you wish to delete. To disable the firewall, type “sudo ufw disable.”

Remember, disabling the firewall leaves your system vulnerable to an attack, and thus should be avoided if possible.

If you must disable the firewall, prioritize re-enabling it as soon as the intended task is completed.


Firewalls are an essential tool in network security and protection against cyberattacks. UFW firewall provides a simple and easy-to-use option for Ubuntu Linux users.

In this article, we have provided an overview of firewalls and UFW firewall and explored the steps for the installation, enabling, and configuring of UFW firewall. By following the steps outlined, users can customize the firewall to fit their specific network security needs and ensure that their data and systems are secure.

In this article, we’ve discussed the importance of firewalls in securing networks and protecting against cyberattacks. Specifically, we’ve explored UFW firewall in Ubuntu Linux, its features, and installation process.

Additionally, we’ve provided a detailed overview of the steps required to configure the UFW firewall settings, including setting up IPv6 and default policies, allowing outgoing connections, modifying rules, deleting, and disabling firewall rules. By following the outlined procedures, users can tailor the firewall to meet their specific network security requirements, safeguarding their data and systems from malicious activities.

The takeaway from this article is the significance of having a firewall and the ease of use of UFW firewall and how they can be configured to protect against cyber threats.

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