Open Source C Firewall Software for Windows

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.

simplewall is an open-source Windows application that provides a user-friendly firewall control interface powered by Windows Filtering Platform (WFP), enabling users to block or allow outgoing and incoming network connections without diving into complex OS settings or command-line tools. The app presents a clean, intuitive UI where users can define rules based on process names, IP addresses, ports, and protocols, making it possible to restrict apps from accessing the internet or control specific traffic flows with fine granularity. Because simplewall leverages WFP directly, it operates at a low level in the network stack, ensuring reliable enforcement of rules system-wide while remaining lightweight. It also includes optional modes like blocking all inbound or outbound traffic except what’s explicitly allowed, and supports temporary rule application, logging, and diagnostic views to help users understand what traffic is being blocked or permitted.

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.

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).

CacheGuard Gateway is a free and open-source Unified Threat Management (UTM) solution, a Web Application Firewall (WAF), and a Quality of Service (QoS) platform designed to optimize WAN traffic. To obtain a CacheGuard Gateway appliance, download CacheGuard-OS and install it on the bare-metal or virtual machine of your choice. It’s that simple and completely free. The UTM includes a firewall, web antivirus, VPN server, and a URL-filtering and SSL-inspection web proxy. The WAF operates in conjunction with a reverse proxy, web application load balancer, and SSL offloader, and is capable of blocking malicious requests as well as traffic from IP addresses with poor reputations. The QoS manager enables traffic shaping to prioritize critical network flows, load balance multiple WAN links, and cache web traffic.

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).

wipfw - IPv4 packet filter and traffic shaper for Windows based on IPFW (FreeBSD firewall).

Blocks "known bad" IP-addresses from accessing your machine, especially corporate/governmental agencies. This is a fork of PeerGuardian 2, fixing various Vista/Win7 problems.

VTD-XML is the next generation XML parser/indexer/editor/slicer/assembler/xpath-engine that goes beyond DOM, SAX and PULL in performance, memory usage, and ease of use.

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.

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.

Bored of having HTTP-only connection to the Internet? Tired of being unable to connect to irc through a HTTP proxy? desproxy (a TCP tunnel for HTTP proxies) just makes you able to tunnel all your TCP traffic through a HTTP proxy! Keywords: HTTP pr

Nodogsplash offers a simple way to provide restricted access to an internet connection. It is intended for use on wireless access points running OpenWRT (but may also work on other Linux-based devices).

It is a versatile DNS Proxy server with DNS firewall which filters DNS traffic between local computer and DNS servers with flexible rules, supports blocking by IP geography, caching, import/export rules into XML. With a click of a button acts as a DNS proxy (or DNS server), supports multiple client authentication methods, calculates statistics for DNS servers and proxy clients, supports load balancing between multiple upstream DNS servers.

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

Flexible web-based firewall log analyzer, supporting netfilter and ipfilter, ipfw, ipchains, cisco routers and Windows XP system logs, and mysql or postgresql database logs using the iptables ULOG or NFLOG target of netfilter others mapped to the ulogd format with a view. Fully supports IPv6 for database logs, and netfilter and ipfilter system file logs. Also supports Maxmind's GeoIP version 2 location databases. For Linux, FreeBSD, OpenBSD, Solaris, OSX,etc.

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,...)

m0n0wall is a powerfull Router Application Platform.

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.

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 windows c++ program to test various libraries on various routers to forward ports on routers.

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.

Bi-directional Wireless Sensor Line Protocol(Bi-WSLP) is a sensor network communication protocol based on a line topology, which is common in outdoor monitoring cases for IoT(Internet of Things). Bi-WSLP runs fast and provides a response rapidly, yet it takes a small code size occupies small memory. Bi-WSLP can be easily ported to various hardware platforms because it is coded in C, which is the most popular programming language for embedded systems. In addition, Bi-WSLP allows transmission of large-size data such as still images as well as common sensor data such as temperature and humidity. Bi-WSLP can be modified to conform to the IEEE 802.15.4 standard. Bi-WSLP supports bidirectional data transmission, so it allows a user not only to control the operation of sensor nodes immediately, but also to receive responses to the user almost in real-time.