Open Source Linux Firewall Software

Smoothwall is a best-of-breed Internet firewall/router, designed to run on commodity hardware and to provide an easy-to-use administration interface to those using it. Built using open source and Free software, it's distributed under the GNU Public License.

VTun is the easiest way to create Virtual Tunnels over TCP/IP networks with traffic shaping, compression, and encryption. It supports IP, Ethernet, PPP and other tunnel types. VTun is easily and highly configurable. VPN, Mobile IP, Shaping, etc

Privoxy is a non-caching web proxy with advanced filtering capabilities for enhancing privacy, modifying web page data and HTTP headers, controlling access, and removing ads and other obnoxious Internet junk. Privoxy has a flexible configuration and can be customized to suit individual needs and tastes. It has application for both stand-alone systems and multi-user networks.

The UPnP PortMapper can be used to easily manage the port mappings/port forwarding of a UPnP enabled internet gateway/router in the local network.

The IPCop Firewall is a Linux firewall distribution. It is geared towards home and SOHO users. The IPCop web-interface is very user-friendly and makes usage easy.

PeerGuardian is a privacy oriented firewall application. It blocks connections to and from hosts specified in huge blocklists (thousands or millions of IP ranges). Its origin seeds in targeting aggressive IPs while you use P2P. PeerGuardian Linux: Not developed actively anymore. Team might still be around. Some unreleased changes on git. Outdated technology. Peerguardian OS X: Not developed anymore. We've lost contact with the OS X developer. PeerGuardian Windows: Not developed anymore. It's highly recommended to use PeerBlock instead, which is a continuation of PeerGuardian's development in Windows, with bug fixes and support for Windows Vista and Windows 7. Collaboration with peerblock.com is welcome! PeerGuardian is an open project. Not only is its source code open for you to read, use, and modify - but the project is open for you to join and contribute in any form (code, documentation, bug reports, web and support).

OPNsense is an open source, easy to use and easy to build FreeBSD based firewall and routing platform. OPNsense includes most of the features available in expensive commercial firewalls, and more in many cases. Mission statement of the project: "Give users, developers and businesses a friendly, stable and transparent environment. Make OPNsense the most widely used open source security platform."

Endian Firewall Community (EFW) is a "turn-key" linux security distribution that makes your system a full featured security appliance with Unified Threat Management (UTM) functionalities. The software has been designed for the best usability: very easy to install, use and manage and still greatly flexible. The feature suite includes stateful packet inspection firewall, application-level proxies for various protocols (HTTP, FTP, POP3, SMTP) with antivirus support, virus and spam-filtering for email traffic (POP and SMTP), content filtering of Web traffic and a "hassle free" VPN solution (based on both OpenVPN and IPsec).

OpenSnitch is a GNU/Linux port of the Little Snitch firewall. You can launch the GUI from the icon or from the system menu. The daemon will start intercepting connections, prompting you to allow or deny them. If you don't apply an action, after 15 seconds (configurable) it'll apply the default action configured. When you open the GUI, you'll see all the connections and processes that the daemon has intercepted. Double click on a row to view the details of a process, rule, host or user. Once you know which are the common processes, IPs and hosts that your machine is connecting to, you can start creating permanent rules (Duration: always) to deny or allow them. You can also convert temporary rules to permanent by right-clicking on a temporary rule or by double-clicking on it, and then edit it. By default OpenSnitch UI listens on a local Unix socket in /tmp/osui.sock.

Firewall Builder is a GUI firewall management application for iptables, PF, Cisco ASA/PIX/FWSM, Cisco router ACL and more. Firewall configuration data is stored in a central file that can scale to hundreds of firewalls managed from a single UI. A message from project maintainers: After working on Firewall Builder for many years it is with some sadness that Vadim and I are announcing that we have suspended all development activity for this project. Firewall Builder has been a great project to work on and we have truly appreciated all the support and positive feedback that the user community has provided. Without you we wouldn’t have been able to keep things going this long. You might be wondering why we are doing this... We had an exciting opportunity come up to start a company developing advanced security automation solutions. This was a chance of a lifetime that we just couldn’t pass up and unfortunately it means that we no longer have time available to work on improv

Siproxd is a proxy/masquerading daemon for the SIP protocol. It allows SIP clients (softphones & hardphones) to work behind an IP masquerading firewall or router.

A java wrapper for popular "libpcap" and "WinPcap" libraries. Accurate full API translation. Packet buffers delivered with no copies. Send custom packets, gather statistics. Comprehensive and easily extensible DPI engine.

Those who have read past the "Malware" warning can be assured there is absolutely no malware in this OS or in the download. This warning comes from the "netcat" binary included in the download as a DOS time client. Unfortunately netcat has code that is flagged as malware. FREESCO, a NAT/firewall router/server based on Linux and runs on a single 1.44MB floppy. Freesco is very powerful and versatile and can connect multiple home or small office networks to most types of Internet connections including dialup.

SSHGuard protects hosts from brute-force attacks against SSH and other services. It aggregates system logs and blocks repeat offenders using several firewall backends, including iptables, ipfw, and pf.

A client for the MikroTik RouterOS API protocol, written in PHP. Easy, tested and documented. All feedback welcomed.

SS5 is a socks server for Linux, Solaris and FreeBSD environment, that implements the SOCKS v4 and v5 protocol.

A utility for detecting and resisting BIDIRECTIONAL ARP spoofing. It can anti-spoof for not only the local host, but also other hosts in the same subnet. It is as well a handy helper for gateways which don't work well with ARP.

BASE is the Basic Analysis and Security Engine. It is based on the code from the Analysis Console for Intrusion Databases (ACID) project. This application provides a web front-end to query and analyze the alerts coming from a SNORT IDS system.

ModSecurity is a web application firewall that can work either embedded or as a reverse proxy. It provides protection from a range of attacks against web applications and allows for HTTP traffic monitoring, logging and real-time analysis.

Netdeep Secure is a Linux distribution with focus on network security. Is a Next Generation Open Source Firewall, which provides virtually all perimeter security features that your company may need. It offers Web content filters, ensuring better performance of the network, allowing users to use the service efficiently and securely, providing a deep control of the use of the Web access service, blocking access to unwanted websites, Virus, Spam, Applications and intrusion attempts. Its configuration is made entirely by the web interface.

A Linux port of the OpenBSD/FreeBSD Cryptographic Framework (OCF). This port aims to bring full asynchronous HW/SW crypto acceleration to the Linux kernel, OpenSwan, OpenSSL and applications using DES, 3DES, AES, MD5, SHA, PublicKey, RNGs and more.

The WiFi Guard Dog project is a complete and embeddable captive portal solution for wireless community groups or individuals who wish to open free HotSpots while preventing abuse of their connection. Go to dev.wifidog.org to download the latest version.

ProxySQL is an open source, high performance, high availability, database protocol-aware proxy for MySQL. It was created due to a lack of high performance open source proxies, and is able to scale millions of connections across hundreds of thousands of backend servers, all while getting the freedom of being open source. ProxySQL provides end-to-end MySQL connection handling, real-time statistics and database traffic inspection. It's got failover detection, rich query rule definitions, and a database firewall that protects your database from malicious activity or problematic application deployments. ProxySQL is trusted by numerous organizations throughout the world to meet their MySQL scalability and High Availability goals.

iplist is a list based packet handler which uses the netfilter netlink-queue library (kernel 2.6.14 or later). It filters by IP-address and is optimized for thousands of IP-address ranges.

Enables tunneling of network connections through restrictive HTTP proxies. Features: Portmapping, SOCKS4, SOCKS5, web-based admin interface, possibility to use standalone server (perl) or hosted server (PHP), optional authorization from LDAP or MySQL