Open Source C Firewall Software

Advanced Onion Router is a portable client for the OR network and is intended to be an improved alternative for Tor+Vidalia+Privoxy bundle for Windows users. Some of the improvements include UNICODE paths, support for HTTP and HTTPS proxy protocols on the same Socks4/Socks5 port with HTTP header filtering that generates fake identity-dependent headers every time the identity is changed (proxy chains are also supported), support for NTLM proxies, a User Interface that makes Tor's options and actions more accessible, local banlist for forbidden addresses, private identity isolation, a point-and-click process interceptor that can redirect connections from programs that don't support proxies, also giving them fake information about the local system and support for .onion addresses. Also, it can estimate AS paths for all circuits and prevent AS path intersections, it can restrict circuits to be built using only nodes from different countries, can change circuit lengths and more.

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.

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).

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.

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.

The Nemesis Project is designed to be a command line based, portable human IP stack for UNIX-like and Windows systems. The suite is broken down by protocol, and should allow for useful scripting of injected packets from simple shell scripts.

MailCleaner Open Source Edition is now discontinued but will continue under the spamtagger project https://github.com/SpamTagger [antispam] MailCleaner is an anti-spam / anti-virus filter SMTP gateway with user and admin web interfaces, quarantine, multi-domains, multi-templates, multi-languages. Using Bayes, RBLs, Spamassassin, MailScanner, ClamAV. Based on Debian. Enterprise ready. MailCleaner is an anti spam gateway installed between your mail infrastructure and the Internet. It includes a complete GNU/Linux OS and a graphical web interface for user and administrative access. It comes in the form of virtual machine templates.. - fully compatible with any SMTP mail server (Exchange, Zimbra, O365,...)

Bypass is an IP forwarding/tunneling tool which can be used where limited bypassing of a firewall is necessary, but relaxing the restrictions in the actual firewall is not an option. The aim is for bypass to be automatic and transparent.

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.

Bootable CD Forensics/Virus Scanning/Recovery/PenTesting platform

Knocker is a simple, versatile, and easy-to-use TCP security port scanner written in C, using threads. It is able to analyze hosts and the network services which are running on them. It is available for Linux, FreeBSD, Unix, and Windows95/98/2000.

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.

This project will serve as a central hosting/bug tracking center for modifications to the SmoothWall.org firewall distribution. Support and information for the "mods" posted here can be found on the SmoothWall.org forums, the SmoothWall.org IRC server, or

tgcd is a simple Unix network utility to extend the accessibility of TCP/IP based network services beyond firewalls. This can also be used by network analysts and security experts for penetration testing and analyze the security of their network. It's written in C Language.

Geo Firewall performs blocking of network traffic based on geography (geo IP), allows to add custom subnets, allows exceptions on ports for incoming traffic for specific geography, keeps visual and persistent logs, shows statistics, automatically updates geographical database.

Collection of open source security tools that enhance the ability of people and companies to secure their environment. These tools will build upon the foundation laid by the security community.

Vuurmuur is a powerful firewall manager for Linux/iptables. Vuurmuur supports traffic shaping and live monitoring. It has an easy to learn configuration that allows both simple and complex configurations, and can be fully configured through the Ncurses GUI. Vuurmuur supports NAT, Port Forwarding and has IPv6 support.

AGT is a powerful console frontend to iptables, supporting nearly all of the iptables extensions. All options can be specified in a configuration file with similar syntax to 'ipf' and 'ipfw'.

Campagnol is a decentralized VPN over UDP tunneling. It uses UDP hole punching to open connections through NAT/firewall and OpenSSL's DTLSv1 implementation for mutual authentication and encryption.

Dave's Naughty Stuff Blocker. This is an open source solution to allow administrators to filter and redirect selected "inappropriate" sites based on a list of specific sites and/or strings.

IPFIRE-wall is a framework that implements a network firewall. It can be used in desktop systems and in simple network configurations, providing a friendly graphical interface and a simple installation procedure. Also unprivileged users can personalize.

Snort_inline is a modified version of Snort. It accepts packets from iptables, instead of libpcap. It uses new rule types to tell iptables if the packet should be dropped or allowed to pass based on the Snort rules.

Udpproxy is very simple but usefull tool for udp traffic forwarding. Can be used if you can't or don't want to mess with kernel level forwarding.

AMaViS is a script that interfaces a mail transport agent (MTA) with virus scanners.

Anoubis is a Security Suite which implements a secured environment for applications. The core of the suite is an Application Firewall alongside with a Sandbox. Mechanisms to assure the authenticity of files, directories and applications are provided.