While you are on internet it is important to protect your most valuable systems against threats and attacks. You are the IT administrator who need to protect by adding a firewall protection. It ensure that the traffic entering and leaving the secured LAN is accessing the right applications on the right systems. While there are many commercially available firewalls, here is a list of 12 open source alternatives to commercial software.
1. Coyote Linux
Coyote Linux is a small embedded distribution of Linux designed to work as a firewall for small to medium sized networks (less than 200 users). Current plans for Coyote Linux include a completely overhauled administration interface, much more robust security features, failover clustering, hardware security accelerator support, and much more.
Firestarter is a free and open source personal firewall tool that uses the Netfilter (iptables/ipchains) system built into the Linux kernel. Firestarter has the ability to control both inbound and outbound connections, provides a easy to use graphical interface for configuring firewall rules and settings. It also provides real-time monitoring of all network traffic for the system.
The IPCop Firewall is a Linux firewall distribution that is geared towards home and Small Office Home Office users. The IPCop web-interface is very user-friendly and makes usage easy.
IPFilter is an open source software package that provides firewall services and network address translation (NAT) for UNIX-like operating systems. IPFilter supports both IPv4 and IPv6 protocols, and is a stateful firewall.
IPFire is a free Open Source hardened Linux appliance distribution designed for use as a firewall. It offers corporate-level network protection for anyone who needs it, from home users all the way up to large corporations, school networks and authorities. It can be maintained via a Web interface.
iptables is a user space application program that allows a system administrator to configure the tables provided by the Linux kernel firewall. It is command line program used to configure the Linux 2.4.x and 2.6.x IPv4 packet filtering ruleset. It is targeted towards system administrators. The iptables package also includes ip6tables. ip6tables is used for configuring the IPv6 packet filter.
m0n0wall is an embedded firewall distribution of FreeBSD, one of the BSD operating system descendants. It provides a small image which can be put on Compact Flash cards as well as on CDROMs and hard disks. It runs on a number of embedded platforms and generic PCs. The PC version can be run with just a Live CD and a floppy disk to store configuration data, or on a single Compact Flash card (with an IDE adapter). This eliminates the need for a hard drive, which reduces noise and heat levels.
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.
Shorewall (or the Shoreline Firewall) is an open source firewall tool for Linux that builds upon the Netfilter (iptables/ipchains) system built into the Linux kernel, making it easier to manage more complex configuration schemes.
The Smoothwall Open Source Project was set up in 2000 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. Smoothwall is a Linux distribution designed to be used as an open source firewall. Designed for ease of use that is configurable via a web-based GUI and it requires very little or no knowledge of Linux to install or use.
Untangle’s is a free open source Firewall that filters traffic based on IP address, protocol and port, which enables administrators to designate which systems and services (HTTP, FTP, etc.) are publicly available. It run as a transparent bridge to complement pre-existing firewalls and control inbound and/or outbound access to specifics IPs and ports.
Vyatta manufactures software-based virtual router, virtual firewall and VPN products for Internet Protocol networks (IPv4 and IPv6). A free download of Vyatta has been available as open source package that is a specialized Debian-based Linux distribution with networking applications such as Quagga, OpenVPN, and many others.