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Best Firewall Technologies for Linux

The right Linux firewall should do more than protect your desktops and servers from network intrusion. While Linux distros come bundled with free firewall applications, you might need to take a few steps to activate them. The fact that some of these IP tables aren’t user-friendly makes them less desirable. Luckily, some distros come with UFW- Uncomplicated Firewall, which makes the activation process easier.

Even better, there are firewall applications that can help both experienced and inexperienced users to protect their devices, though not all are free. They can help you block rouge IPs, prevent bad packets from interacting with your device and monitor ports.

While new users can be comfortable with simple applications that require less customization, those who need more customization might do well with software that provides advanced command options. The ideal option for you will depend on what works for you best.

Here are some of the best firewall technologies for Linux you can use:


If you are looking for a sleek and easy-to-use firewall distro, then ClearOS should be among your top option. Unlike other applications that are designed with the user experience as an afterthought, ClearOS is designed to make the configuration journey and overall use easy. You can take as short as ten minutes to set it up.

When setting up, you will be urged to choose between starting it in Public Server or Gateway modes- depending on your preference. Once you make a choice, you will be given all the necessary information needed for administering and accessing your firewall remotely.

The fact that it is user-friendly means that it won’t take a lot of effort to familiarize yourself with the processes, settings, and features. You can use the ‘Getting Started’ guide to navigate the distro. Setting up the rules for your firewall is equally as painless and easy. While you can use it in its free ‘community’ version, you can always pay for the ‘business’ and ‘home’ versions- depending on the features you want.


IPFire is designed for use by people who aren’t familiar with firewalls and networking. It is easy to set up and quite user-friendly. You can enjoy a variety of features while using it, such as intrusion detection, which can make using your device easy.

During installation, you can configure your network into different color-coded segments. While the green segment will stand for safe connections from all normal clients who are locally wired to the network, the red segment will represent the entire internet.

Traffic will only be allowed to pass from the red to the green segment if it meets your predefined rules. The red and green segments are the default options, but the device also allows you to include an orange segment for public servers (DMZ) and a blue segment for wireless connections. This can be especially helpful for businesses or individuals that take risk assessment seriously. Once you are done setting up your device, you can configure add-ons and additional options through the user-friendly and intuitive interface.


While being based on HardenedBSD for long term support, OPNsense is quite easy to use. It was initially created as a fork of pfSense, a more established firewall, and offers LibreSSL over OpenSSL. The team behind the project claimed that they wanted to circumvent some of the licensing issues with pfSense as well as create a more secure firewall. The firewall is renowned for its weekly updates that ensure that it can respond to threats fast.

It comes with features that are often found only in commercial firewalls, such as intrusion detection and forward caching proxy. Its GUI, which is written in Phalcon PHP, is easy to use and includes a simple search bar and a System Health Module. You can use the module’s interactive and visual feedback features to assess the health of your network. It also allows you to conduct further analysis of the data by exporting it in CSV format.

OPNsense runs on an Inline Intrusion Prevention System- a form of Deep Packet Inspection that does more than block ports and IP addresses. It can inspect the individual connections and data packets and prevent them from reaching the sender.


Although it is quite different from IPFire, IPCop does utilize similar color-coding schemes to represent different connections. Green represents the LAN, while crimson represents the web. Blue stands for wireless customers and orange represents the DMZ. Installing the firewall is relatively simple.

If you are a novice user, working with the default options might suffice, unless you are using a special network configuration. Since IPCop’s setup image is fairly small, you can easily copy it on a flash drive or DVD.

It boasts real-time charts that can provide you with information about your LAN installation and your firewall’s health. With its caching proxy feature, you can cache pages you frequently visit for easy access.

How to Test if Your Firewall is Working

If you want to know whether your firewall is working, you can use a firewall tester tool. These tools mainly have two Perl scripts- a listening sniffer and a packet injector. The latter injects custom packets with a specific data signature into your network.

The sniffer, on the other hand, listens for such marked packets. Both scripts then write log files in the same form. Any difference between the files they produce signifies the packets that didn’t reach the sniffer due to the filter rules, as long as the injector and sniffer run on both sides of the firewall.

Your network security matters, which is why you should never ignore investing in a reliable firewall. The ideal one for you will trickle down to the features you desire. Take time to assess the different firewalls to choose one that suits your needs. If you need help navigating your operating system or firewalls, you can always rely on the many free Linux books on the internet for information.

Originally posted 2020-11-11 21:15:12. Republished by Blog Post Promoter

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