Best Open Source Firewall in 2026: pfSense, OPNsense, IPFire, OpenWrt and VyOS Compared

The best open source firewall in 2026 for most people is OPNsense, with pfSense CE a very close second: both are free, FreeBSD-based, run on any small x86 box with two network ports, and become a near next generation firewall (NGFW) once you add intrusion prevention. Pick IPFire for a Linux-based appliance, OpenWrt for routers and Wi-Fi hardware, and VyOS if you want a CLI router built for engineers. I have run open source firewalls since 2005 and today my homelab sits behind pfSense, so the notes below come from daily use, not a spec sheet.

Quick answer: which open source firewall should you choose?

1. Best overall: OPNsense 26.7. Fully open source, modern UI, two major releases a year, Zenarmor plugin for application control.
2. Best documented: pfSense CE 2.9.0. The largest community, the most tutorials and packages (pfBlockerNG, Suricata, HAProxy).
3. Best Linux firewall appliance: IPFire 2.29. Simple zone model (red, green, blue, orange), built-in IPS and location blocking.
4. Best for routers and Wi-Fi: OpenWrt 25.12. Replaces the firmware on supported consumer routers.
5. Best for network engineers: VyOS. Junos-style CLI, BGP/OSPF, scripted configuration.
6. Easiest GUI, freemium: Arista Edge Threat Management NG Firewall (formerly Untangle). Free core with paid apps.
7. Free but not open source: Sophos Firewall Home Edition. Full Sophos features for home use, capped at 4 cores and 6 GB RAM.
8. Legacy: Endian Firewall Community. Still downloadable, but releases have stalled.

Open source firewall comparison table (October 2026)

Versions are taken from each project's release notes in October 2026; check the links in each section before you download, because point releases land every few weeks.

What makes a firewall "next generation"?

Gartner defines an NGFW as a deep packet inspection firewall that goes beyond port and protocol blocking to add application-level inspection, intrusion prevention and threat intelligence from outside the firewall. In open source terms that usually means:

• Stateful firewall, NAT and routing (every option above);
• Intrusion detection and prevention with Suricata or Snort rule sets;
• IP and DNS blocklists (pfBlockerNG on pfSense, the IPFire DBL, Unbound blocklists on OPNsense);
• Application awareness (layer 7) through Zenarmor on OPNsense or the paid apps on Arista NG Firewall;
• VPN: WireGuard, OpenVPN and IPsec are free on all of the main platforms.

If you only need a solid stateful firewall and VPN, any of the first five is enough. If you need "block TikTok but allow YouTube" style rules without writing them yourself, you need an application-aware engine.

1. OPNsense: best open source firewall overall

OPNsense forked from pfSense in 2015 and has become the most actively developed open source firewall. Version 26.7 "Xenial Xenops" shipped on 15 July 2026 on FreeBSD 15.1, with OpenVPN 2.7, PHP 8.5 and firewall rules, interface assignments and gateway groups moved to the MVC/API framework (release notes). Point releases (26.7.1 onwards) follow every couple of weeks with security fixes.

Why pick it

• Fully open source under the BSD licence, with a free Community Edition and a paid Business Edition that is the same code on a slower, more tested schedule.
• Suricata IDS/IPS is built in, and the free Zenarmor plugin adds application identification and per-app rules.
• Clean web UI, a full REST API and two major releases a year (January and July).
• WireGuard, OpenVPN, IPsec, Kea DHCP, Unbound DNS with blocklists, multi-WAN and CARP high availability are all free.

Watch out for: frequent updates mean you should read the release notes before each one, and a few legacy pages are still being migrated to the new framework. Zenarmor deep packet inspection uses noticeable CPU and RAM.

Hardware: the OPNsense hardware guide lists a 1 GHz dual-core CPU and 3 GB RAM as the minimum, and recommends more RAM and an SSD once you use IDS/IPS or reporting.

For DNS on OPNsense, see my comparison of Dnsmasq vs Unbound on OPNsense.

2. pfSense CE: best documented and the one I run

pfSense Community Edition is the firewall most people learn on, and it is what protects my Proxmox cluster and TrueNAS at home. Netgate's versions page lists pfSense CE 2.9.0 (20 August 2026) as the current CE release, alongside pfSense Plus 26.07 for Netgate hardware and subscribers.

Why pick it

• Free and open source (Apache 2.0) with the biggest pool of guides, forum answers and videos of any firewall.
• Packages turn it into an NGFW: Suricata or Snort for IPS, pfBlockerNG for GeoIP and DNS blocking, HAProxy, ACME certificates, FRR for BGP/OSPF.
• Rock-solid stateful filtering, VLANs, multi-WAN, CARP high availability, WireGuard, OpenVPN and IPsec.

Watch out for: CE releases come less often than Plus releases, the UI looks older than OPNsense, and some packages lag behind. New installs use the Netgate online installer, which asks you to register a free account. If you want a hands-on comparison, read pfSense vs OPNsense.

Hardware: Netgate's minimum requirements are a 64-bit amd64 CPU, 1 GB RAM and 8 GB disk. In practice I recommend 4 GB RAM and an SSD, more if you run Suricata on several interfaces.

3. IPFire: best Linux-based firewall appliance

IPFire is a hardened Linux distribution built only to be a firewall. It uses a simple colour-coded zone model (red for WAN, green for LAN, orange for DMZ, blue for Wi-Fi) that makes rule planning easy. The 2.29 branch receives regular Core Updates: Core Update 200 (early 2026) moved to the Linux 6.18 LTS kernel and introduced the beta IPFire DBL domain blocklist.

Why pick it: GPL licensed, Suricata IPS and location-based blocking built in, OpenVPN and IPsec, a small add-on catalogue, and it runs on x86_64 and ARM64.

Watch out for: fewer add-ons and less flexibility than the BSD firewalls, and no built-in application-aware engine.

Hardware: the IPFire requirements say 1 GB RAM and 2 GB disk are enough for a basic install, but plan for 5 to 6 GB RAM with the proxy, URL filter, IPS and DNS firewall, and 8 GB if you use everything.

4. OpenWrt: best for routers and Wi-Fi hardware

OpenWrt is not a dedicated firewall distribution, it is replacement firmware for routers, but its nftables-based firewall (fw4), VLAN support, WireGuard and SQM queue management make it the best free firewall for anyone whose "firewall" is a Wi-Fi router. OpenWrt 25.12 (first released March 2026) replaced the old opkg package manager with apk, so older guides that use opkg install need the new syntax (25.12 release notes).

Pick it if you want to keep one box for routing and Wi-Fi, or run on low-power ARM hardware. Skip it if you need a full IDS/IPS stack and rich reporting; use OPNsense or pfSense on a mini PC instead and keep the router as an access point.

5. VyOS: best for network engineers

VyOS is a Debian-based router and firewall configured entirely from a Junos-like CLI, with commit and rollback, BGP, OSPF, VRFs, WireGuard and zone-based firewalling. VyOS 1.5 "Circinus" became the LTS release on 31 March 2026 with an optional VPP-accelerated dataplane.

Licensing note: the source code is open, but prebuilt LTS images are for subscribers (contributors can get them for personal use). The free options are the rolling release and the VyOS Stream images. That makes VyOS ideal for labs, cloud edges and people who automate with Ansible, and less ideal if you want a point-and-click GUI.

6. Arista Edge Threat Management NG Firewall (formerly Untangle)

Untangle NG Firewall became part of Arista in 2022 and now lives at edge.arista.com. Version 17.x is current (17.5 added a refreshed admin UI and a Dynamic Blocklists app). Arista's FAQ says the core platform and open source apps are free: the datasheet lists Firewall, Intrusion Prevention, Phish Blocker, Ad Blocker, Captive Portal, OpenVPN, Tunnel VPN and Reports at no cost, with lite versions of Web Filter, Application Control, Virus Blocker and Spam Blocker. WireGuard, IPsec, WAN Balancer, Policy Manager and SSL Inspector need a subscription, and home subscriptions were withdrawn in 2024, with expired installs falling back to the free feature set. It is still the easiest UI to learn, but it is no longer the free all-rounder it was a decade ago. I cover what changed in Untangle in 2026: is it still free?.

7. Sophos Firewall Home Edition: free, not open source

Sophos Firewall Home Edition gives home users the full commercial Sophos Firewall feature set (IPS, web filtering, application control, TLS inspection) at no cost. The limits: home and non-commercial use only, a cap of 4 CPU cores and 6 GB RAM, community-only support and seven days of report data. It is a good choice if you want enterprise-style features at home and do not mind closed source.

8. Endian Firewall Community: legacy only

Endian still offers a free Community edition, but the last listed community release is 3.3.x from 2020. It works, and existing installs keep running, but I would not build a new firewall on it in 2026 when OPNsense, pfSense CE and IPFire are all actively patched.

How to choose: a simple decision path

• You want one answer: OPNsense.
• You are learning networking or following a course: pfSense CE, because almost every tutorial uses it.
• You prefer Linux and a simple appliance: IPFire.
• Your hardware is a consumer Wi-Fi router: OpenWrt.
• You live in a CLI and run BGP: VyOS.
• You need application control for free: OPNsense plus Zenarmor Free Edition.
• You want commercial features at home and do not care about open source: Sophos Home Edition.

Hardware I recommend for a home or small office firewall

• A fanless mini PC with an x86-64 CPU (Intel N100/N150 class or better) and two to four Intel i226 or similar 2.5 GbE ports;
• 8 GB RAM if you will run Suricata or Zenarmor, 4 GB otherwise;
• a 64 GB or larger SSD (logs and IDS alerts write a lot);
• optionally run it as a VM on Proxmox with PCIe passthrough of the NICs, which is how I test new releases before touching my main firewall.

How to install a free firewall (the short version)

1. Download the ISO or USB image from the official site only (opnsense.org, pfsense.org, ipfire.org, openwrt.org, vyos.io) and verify the checksum.
2. Write it to a USB stick with Rufus, balenaEtcher or dd.
3. Boot the firewall box, install to the SSD, and assign WAN and LAN interfaces at the console.
4. Browse to the LAN address (for example https://192.168.1.1), change the default password and run the setup wizard.
5. Update to the latest point release, then add IDS/IPS, blocklists and VPN one at a time so you can see what each changes.

Courses if you want to go deeper

pfSense: Network Security and Firewall Management

OPNsense Firewall: Complete Guide to Network Security

Untangle / Arista NG Firewall: Network Security

Final thoughts

Open source firewalls are better in 2026 than they have ever been: OPNsense and pfSense CE both ship current FreeBSD bases, WireGuard is standard, and free IPS rule sets cover most threats a home lab or small business will see. What has changed is the freemium side: Untangle's free tier has shrunk under Arista, and VyOS LTS images now sit behind a subscription. If you are starting today, install OPNsense or pfSense CE on a two-port mini PC, add Suricata and a blocklist, and you will have a firewall that outperforms most consumer routers by a long way.

If you also want visibility of what happens behind the firewall, pair it with a SIEM such as Wazuh on Ubuntu 24.04.