IPCop!

pfSense is a free, open source customized distribution of FreeBSD tailored for use as a firewall, and router. In addition to being a powerful, flexible firewalling and routing platform, it includes a long list of related features and a package system allowing further expandability without adding bloat and potential security vulnerabilities to the base distribution, making it a fully qualified UTM device. pfSense is a popular project with more than 1 million downloads since its inception, and proven in countless installations ranging from small home networks protecting a PC and an Xbox to large corporations, universities and other organizations protecting thousands of network devices. »

IPFire is a server distribution with intended to use as a firewall. It focuses on flexibility, and scales from small to middle sized business networks and home networks.

Home of the OPNsense project, free Open Source Firewall, router, UTM, load balancing, multi WAN, FreeBSD, Linux, High Availability CARP

Zeroshell is a Linux distribution for servers and embedded devices aimed at providing the main network services a LAN requires. It is available in the form of Live CD or Compact Flash image and you can configure and administer it using your web browser.

VyOS is a community fork of Vyatta , a Linux-based network operating system that provides software-based network routing, firewall, and VPN functionality.

Endian Firewall Community (EFW) is a "turn-key" linux security distribution that turns every system into a full featured security appliance with Unified Threat Management (UTM) functionality. The software has been designed with "usability in mind" and is very easy to install, use and manage, without losing its flexibility.

The SmoothWall Open Source Project was set up to develop and maintain SmoothWall Express - a Free firewall that includes its own security-hardened GNU/Linux operating system and an easy-to-use web interface.

OpenContrail is an Apache 2.0-licensed project that is built using standards-based protocols and provides all the necessary components for network virtualization–SDN controller, virtual router, analytics engine, and published northbound APIs. It has an extensive REST API to configure and gather operational and analytics data from the system. Built for scale, OpenContrail can act as a fundamental network platform for cloud infrastructure. The key aspects of the system are: