Workshop: Lock down your Linux system with Firewalld and OpenSnitch
Double Protection

© Lead Image courtesy of Sofia Tolstaya, the author's 10-year-old daughter
For maximum security, you'd better watch traffic in both directions. This hands-on workshop takes you through the steps of setting up firewalls for outgoing as well as incoming traffic.
Linux has a great selection of firewalls for securing stand-alone computers or whole networks. Small LANs usually depend on small routers for security. But what if your Linux machine is exposed on the network and you don't have control over the upstream router or gateway? What if you're working behind one of the millions of smaller routers with out-of-date firmware or missing security patches?
If you're really serious about building a perfectly secure, network-attached Linux workstation, you'll need to fortify the system from two directions: with a host-based firewall for managing incoming connections and with a per-application firewall for controlling outbound traffic. This hands-on workshop will show you how to fortify your system using Firewalld and the OpenSnitch application firewall.
Limiting the Incoming Flow
Network security starts with limiting access to your host from the outer world. One of the most advanced and popular tools for limiting incoming traffic is Firewalld [1], a modern and flexible firewall that replaced the legacy Iptables software a few years ago. Firewalld was introduced as a default network security solution in Fedora 18 and RHEL 7, and consequently, in CentOS 7 as well. The Firewalld firewall is now included in many other mainstream Linux distributions, such as openSUSE and Arch.
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

News
-
OpenMandriva Lx 6.0 Available for Installation
The latest release of OpenMandriva has arrived with a new kernel, an updated Plasma desktop, and a server edition.
-
TrueNAS 25.04 Arrives with Thousands of Changes
One of the most popular Linux-based NAS solutions has rolled out the latest edition, based on Ubuntu 25.04.
-
Fedora 42 Available with Two New Spins
The latest release from the Fedora Project includes the usual updates, a new kernel, an official KDE Plasma spin, and a new System76 spin.
-
So Long, ArcoLinux
The ArcoLinux distribution is the latest Linux distribution to shut down.
-
What Open Source Pros Look for in a Job Role
Learn what professionals in technical and non-technical roles say is most important when seeking a new position.
-
Asahi Linux Runs into Issues with M4 Support
Due to Apple Silicon changes, the Asahi Linux project is at odds with adding support for the M4 chips.
-
Plasma 6.3.4 Now Available
Although not a major release, Plasma 6.3.4 does fix some bugs and offer a subtle change for the Plasma sidebar.
-
Linux Kernel 6.15 First Release Candidate Now Available
Linux Torvalds has announced that the release candidate for the final release of the Linux 6.15 series is now available.
-
Akamai Will Host kernel.org
The organization dedicated to cloud-based solutions has agreed to host kernel.org to deliver long-term stability for the development team.
-
Linux Kernel 6.14 Released
The latest Linux kernel has arrived with extra Rust support and more.