Open Source 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.

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.

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 Outdated technology.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).

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

This is a daemon that emulates Microsoft's Internet Connection Service (ICS). It implements the UPnP Internet Gateway Device specification (IGD) and allows UPnP aware clients, such as MSN Messenger to work properly from behind a Linux NAT firewall.

A Free SOCKS proxy server for Linux, macos and FreeBSD

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.

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.

Fail2Ban monitors log files like /var/log/pwdfail or /var/log/apache/error_log and bans failure-prone addresses. It updates firewall rules to reject the IP address or executes user defined commands. Please see code and download from https://github.com/fail2ban/fail2ban . SF Fail2ban portal might not be up-to-date

OpenVoucher is an open source voucher management / hotspot system for authenticating guests in your wifi or cable network. It is designed to be easy to use for anyone who wants to issue vouchers. For further information and installation how to's, see the project's homepage. The source code is maintained on Github.

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.

Etherwall is a free and open source network security tool that prevents Man in The Middle (MITM) through ARP Spoofing/Poisoning attacks. It Also prevent it from various attacks such as Sniffing, Hijacking, Netcut, DHCP Spoofing, DNS Spoofing, WEB Spoofing, and others. Note: For personal computer use only (client security) if you like this program, please give us your vote at http://sourceforge.net/projects/etherwall/reviews/

Windows Port Knocking. A Windows implementation of port knocking developed to work alongside an existing firewall (the free CHX-I Packet Filter v3.0).

Boundman is an advanced, user-friendly, and sleek application designed to take control over your network connections. It allows you to efficiently manage and block incoming and outgoing traffic for specific .exe files contained within a chosen folder and its subfolders. With its intuitive PyQt5 graphical interface and robust PowerShell scripts, Boundman provides seamless integration with the Windows Firewall for a powerful network management experience.

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.

Coyote Linux is a security centric distribution of Linux designed to provide firewall, VPN service, IP routing, and various other functions.

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.

360-FAAR (Firewall Analysis Audit and Repair) is an offline, command line, firewall policy manipulation tool to filter, compare to logs, merge, translate and output firewall commands for new policies, in Checkpoint dbedit, Cisco ASA or ScreenOS commands, and its one file! Read Policy and Logs for: Checkpoint FW1 (in odumper.csv / logexport format), Netscreen ScreenOS (in get config / syslog format), Cisco ASA (show run / syslog format), 360-FAAR compares firewall policies and uses CIDR and text filters to split rulebases / policies into target sections and identify connectivity for further analysis. 360-FAAR supports, policy to log association, object translation, rulebase reordering and simplification, rule moves and duplicate matching automatically. Allowing you to move rules to where you need them. Build new rulebases from scratch with a single 'any' rule and log files, with the 'res' and 'name' options. Switch into DROPS mode to analyse drop log entries.

Two tools able to edit your ipfilter.dat . These tools are able to edit your ipfilter.dat in order to check for big ranges and to check adjacent ranges . From the creators of ipfilterX , Nexus23 Labs . - Updates in Progress -

iSafer firewall is used to protected your PC against spywares, spamwares. It is also a good example for software developers to understand the basic knowledge about firewall. NOTE: Visit http://isafer.sourceforge.net to see more...

Hogwash is an inline packet scrubber that uses Snort's (www.snort.org) detection engine to drop malicious packets before they reach the target machine.

WinFail2ban scans log files/event viewer and bans IP that makes too many password failures.

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

Morpheus is a windows client for fwknop, the Single Packet Authorization System.

Only for windows XP OpenFirewall is based on two lines of defence first WIPFW ( Kernel-mode driver ) and second tdifw ( application-mode TDI-driver ) . Is a Windows firewall easy to use like the commercial products