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Linux Firewall

We have thousands of posts on a wide variety of open source and security topics, conveniently organized for searching or just browsing.

We’ve all run into UFW on Linux systems that were already in use. When firewall problems show up, they almost never show up in new or surprising ways.  We at Linux Security want to help other admins recognize the kind of UFW problem they’re dea...

On most long-running Linux servers, UFW rules don’t get...

 UFW looks simple until you put it on a long-lived...

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UFW in Linux: Why Firewall Issues Repeat and How to Recognize Them

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We’ve all run into UFW on Linux systems that were already in use. When firewall problems show up, they almost never show up in new or surprising ways.  We at Linux Security want to help other admins recognize the kind of UFW problem they’re dealing with before they start changing rules or chasing symptoms. This page isn’t about fixes yet. The goal is to help you recognize the category of issue so you know where to look next.

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Managing Unintended Exposure from UFW Application Profiles in Linux

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On most long-running Linux servers, UFW rules don’t get removed; they get forgotten. Services change, ports shift, packages come and go, and the firewall stops matching what the box is actually doing. You only notice when you audit it, or when something breaks and nobody remembers why a port was ever opened.

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Why IPv6 Influences Linux Firewall Behavior and Exposure Risks

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Most Linux systems are already dual-stack, whether anyone planned for it or not. IPv4 and IPv6 both sit in the kernel, both accept traffic, and both get evaluated independently before a packet ever reaches a service. That’s normal Linux behavior, not a special case, and it’s where a lot of firewall confusion quietly starts.

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IPFire 2.29 -- Core Update 194: Security Improvements & Critical Bug Fixes

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If you’re managing a network with IPFire, the well-known open-source firewall and network security solution, the newest update is worth your attention. IPFire 2.29 – Core Update 194, isn’t your run-of-the-mill patch with a few subtle adjustments. It’s a deliberate step toward tightening security, improving reliability, and staying ahead of evolving network threats. Updates like this are a serious reminder to keep your defenses sharp with how quickly vulnerabilities can be exploited.

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Managing UFW Firewall on Ubuntu: Benefits, Limitations and Insights

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Iptables are the cornerstone for configuring firewalls and managing network traffic in Linux. For the uninitiated, iptables can be complex and intimidating. However, most Linux distributions provide simpler front-end interfaces to manage iptables rules. Ubuntu's Uncomplicated Firewall (UFW) offers a straightforward way to configure firewall settings without diving into intricate iptables commands.

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IPFire 2.27 Core Update 173: 4G Support and Enhancements

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Get ready to experience the best of IPFire 2.27 – Core Update 173! Not only is this update introducing support for 4G and 5G modems that utilize the QMI interface, but also includes a kernel freshly picked from 6.1’s stable series as well as an array of package updates, security enhancements, and bug fixes so you can be sure your device is always up-to-date with the latest improvements!

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