Browse free open source C Firewall Software and projects below. Use the toggles on the left to filter open source C Firewall Software by OS, license, language, programming language, and project status.

  • Keep company data safe with Chrome Enterprise Icon
    Keep company data safe with Chrome Enterprise

    Protect your business with AI policies and data loss prevention in the browser

    Make AI work your way with Chrome Enterprise. Block unapproved sites and set custom data controls that align with your company's policies.
    Download Chrome
  • Build Securely on Azure with Proven Frameworks Icon
    Build Securely on Azure with Proven Frameworks

    Lay a foundation for success with Tested Reference Architectures developed by Fortinet’s experts. Learn more in this white paper.

    Moving to the cloud brings new challenges. How can you manage a larger attack surface while ensuring great network performance? Turn to Fortinet’s Tested Reference Architectures, blueprints for designing and securing cloud environments built by cybersecurity experts. Learn more and explore use cases in this white paper.
    Download Now
  • 1
    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
    Leader badge
    Downloads: 5,338 This Week
    Last Update:
    See Project
  • 2

    PeerGuardian

    PeerGuardian - a privacy oriented firewall application

    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 Outdated technology.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).
    Downloads: 43 This Week
    Last Update:
    See Project
  • 3
    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.
    Leader badge
    Downloads: 50 This Week
    Last Update:
    See Project
  • 4
    MailCleaner

    MailCleaner

    Anti Spam SMTP Gateway

    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,...)
    Downloads: 5 This Week
    Last Update:
    See Project
  • Gen AI apps are built with MongoDB Atlas Icon
    Gen AI apps are built with MongoDB Atlas

    The database for AI-powered applications.

    MongoDB Atlas is the developer-friendly database used to build, scale, and run gen AI and LLM-powered apps—without needing a separate vector database. Atlas offers built-in vector search, global availability across 115+ regions, and flexible document modeling. Start building AI apps faster, all in one place.
    Start Free
  • 5
    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.
    Downloads: 10 This Week
    Last Update:
    See Project
  • 6
    A Free SOCKS proxy server for Linux, macos and FreeBSD
    Downloads: 13 This Week
    Last Update:
    See Project
  • 7
    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.
    Downloads: 2 This Week
    Last Update:
    See Project
  • 8
    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.
    Leader badge
    Downloads: 1 This Week
    Last Update:
    See Project
  • 9
    A windows c++ program to test various libraries on various routers to forward ports on routers.
    Downloads: 4 This Week
    Last Update:
    See Project
  • Simple, Secure Domain Registration Icon
    Simple, Secure Domain Registration

    Get your domain at wholesale price. Cloudflare offers simple, secure registration with no markups, plus free DNS, CDN, and SSL integration.

    Register or renew your domain and pay only what we pay. No markups, hidden fees, or surprise add-ons. Choose from over 400 TLDs (.com, .ai, .dev). Every domain is integrated with Cloudflare's industry-leading DNS, CDN, and free SSL to make your site faster and more secure. Simple, secure, at-cost domain registration.
    Sign up for free
  • 10
    AMaViS is a script that interfaces a mail transport agent (MTA) with virus scanners.
    Downloads: 1 This Week
    Last Update:
    See Project
  • 11
    The program implements the CIDR merging with whitelisting (network exclusion). Output will be summarized to be as small as possible. The program has been widely used for blacklist merge and optimization.
    Downloads: 1 This Week
    Last Update:
    See Project
  • 12
    Debian packages for PeerGuardian Linux (including the GUI) and its precessor moblock/blockcontrol/mobloquer. 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 origins lie in targeting aggressive IPs while you use P2P. See http://sourceforge.net/projects/peerguardian/
    Downloads: 1 This Week
    Last Update:
    See Project
  • 13
    ADSL4Linux is a program to connect your Linux box via ADSL to the internet in as few steps as possible. This is all done in the easiest possible way. Also contains two Firewalls (ipchains and iptables).
    Downloads: 0 This Week
    Last Update:
    See Project
  • 14
    ReAIM is an AOL Instant Messenger Proxy for iptables-based firewalls. It allows direct connections to be made to hosts behind an address-translating firewall. MSN and Windows Messenger are also supported.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 15
    Amber - a "grey list" for Qmail. Amber sits in the tcpserver chain, not accepting or rejecting mail but deferring connections from new IP addresses for some time (default five minutes) before it starts accepting mail from them.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 16
    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.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 17
    The library implements generic content inspection protocol API compatible with Sendmail Milter, thus allowing various applications and proxies to use Milter-compatible filters without running sendmail itself. It is here to replace Checkpoint\'s OPSEC/CV
    Downloads: 0 This Week
    Last Update:
    See Project
  • 18
    Enable servers behind a firewall to export services to the external networks with the assistance from an externel host as proxy (Jumppoint). The firewall tunnel consists of two parts: a frontend as "Jumppoint" and a backend running behind the firewall
    Downloads: 0 This Week
    Last Update:
    See Project
  • 19
    FOSSWALL project is now merged under the Open Source Security Network (OSSN) project. Open Source Security Network is a community who are dedicated to working in different aspects of IT Security, Network Security, Application Security, Email Security etc
    Downloads: 0 This Week
    Last Update:
    See Project
  • 20
    Fork of the OpenBSD spamd for the FreeBSD operating system. See http://www.openbsd.org/spamd/ for the original spamd documentation. Please, report there only FreeBSD related bugs. If you want join to the project - write mail to the samm user.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 21
    Enable Linux firewall to support connection tracking and NAT of H.323 protocol. It supports RAS, Fast Start, H.245 Tunnelling, Call Forwarding, Signal Proxy/Softswitch, RTP/RTCP and T.120 based audio, video, fax, chat, whiteboard, file transfer, etc.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 22
    Iroffer with mIRC-style DCC Server Protocol that might allow sends through firewalls without reconfigurations (and some more extra features)
    Downloads: 0 This Week
    Last Update:
    See Project
  • 23
    A replacement firmware distribution for the 3com 3CRADSL72 a.k.a 3com wireless 11g (distributed by Ya.com) and its identical twin, the SMC7804WBRA, with an ucLinux kernel based system and associated system tools.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 24
    OpenISP: A suite of ISP Management Software (GPL licensed.) mysqlBind, mysqlApache, mysqlRadius, mysqlSendmail, mysqlISP, mysqlRadacct, mysqlIPM and others. NOTICE: Moved to freshmeat.net and www.openisp.net. For third party wrappers: unixservice.com
    Downloads: 0 This Week
    Last Update:
    See Project
  • 25
    A Simple Middlebox Configuration Protocol (RFC 4540) implementation for Linux. SIMCO is a signaling protocol that can be used by applications (such as SIP B2BUAs) to dynamically control firewalls and Network Address Translators (NATs).
    Downloads: 0 This Week
    Last Update:
    See Project
  • Previous
  • You're on page 1
  • 2
  • Next
Want the latest updates on software, tech news, and AI?
Get latest updates about software, tech news, and AI from SourceForge directly in your inbox once a month.