Open Source C VPN Software

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

The Proton VPN app for Android is intuitive to use, offers lots of useful features, and keeps you secure and private when surfing the internet. Once the app is installed, open it and log in with your Proton VPN username and password. If you are a Proton Mail user, you can access the Proton VPN Free plan by logging in with your Proton Mail username and password. Touch the Quick Connect button to automatically connect to the fastest VPN server for your location. You can also choose to connect to any specific server that is available on your plan. You can now securely and privately browse the internet. The datat traveling between your device and the VPN server is encrypted. Secure Core protects your connection by routing your traffic through multiple servers before it leaves our network, defending you against advanced, network-based attacks.

WireGuard for iOS and macOS is the official WireGuard client implementation for Apple platforms, including iOS, iPadOS, and macOS. The project delivers a native Swift-based application that integrates with Apple’s Network Extension framework to provide secure VPN tunneling with strong performance and reliability. It offers a polished graphical interface that allows users to create, import, and manage WireGuard configurations while maintaining the protocol’s emphasis on simplicity and modern cryptography. The software is designed to work seamlessly within Apple’s ecosystem, supporting keychain storage, system networking controls, and platform security features. Because WireGuard is known for its lean architecture, the Apple client maintains efficient resource usage while delivering fast connection speeds. Overall, wireguard-apple is intended for Apple device users and organizations that require a secure, modern VPN solution fully aligned with the Apple networking stack.

Poptop is an open source implementation of a PPTP server. Running under x86 or embedded Motorola ColdFire architectures Poptop provides full interoperability with the Microsoft PPTP VPN client.

An open-source free cross-platform multi-protocol VPN program, as an academic project from University of Tsukuba, under the Apache License 2.0. The API Suite allows you to easily develop your original SoftEther VPN Server management application to control the VPN Server (e.g. creating users, adding Virtual Hubs, disconnecting a specified VPN sessions) from JavaScript, TypeScript, C# or other languages. SoftEther VPN ("SoftEther" means "Software Ethernet") is one of the world's most powerful and easy-to-use multi-protocol VPN software. It runs on Windows, Linux, Mac, FreeBSD and Solaris. SoftEther VPN is an optimum alternative to OpenVPN and Microsoft's VPN servers. SoftEther VPN has a clone-function of OpenVPN Server. You can integrate from OpenVPN to SoftEther VPN smoothly. SoftEther VPN is faster than OpenVPN. SoftEther VPN also supports Microsoft SSTP VPN for Windows Vista / 7 / 8. No more need to pay expensive charges for Windows Server license for Remote-Access VPN function.

A client implementation of Secure Socket Tunneling Protocol (SSTP) for Linux / Mac OS-X that allows remote access via SSTP VPN to Microsoft Windows 2008 Server. This project has been moved to https://gitlab.com/eivnaes/sstp-client

DSVPN is a Dead Simple VPN, designed to address the most common use case for using a VPN. Runs on TCP. Works pretty much everywhere, including on public WiFi where only TCP/443 is open or reliable. Uses only modern cryptography, with formally verified implementations. Small and constant memory footprint. Doesn't perform any heap memory allocations. Small (~25 KB), with an equally small and readable code base. No external dependencies. Works out of the box. No lousy documentation to read. No configuration file. No post-configuration. Run a single-line command on the server, a similar one on the client and you're done. No firewall and routing rules to manually mess with. Doesn't leak between reconnects if the network doesn't change. Blocks IPv6 on the client to prevent IPv6 leaks. Works on Linux (kernel >= 3.17), macOS and OpenBSD, as well as DragonFly BSD, FreeBSD and NetBSD in client and point-to-point modes. Adding support for other operating systems is trivial.

Securing your network should not require an enterprise budget. CacheGuard is a free open-source network security appliance for startups and growing businesses that need serious protection without the complexity. Install CacheGuard-OS on any x86 machine or VM and get a complete security gateway in under an hour. No plug-ins, no compatibility issues. Everything works out of the box. CacheGuard-OS is not an app, it IS the OS. A fully custom network appliance operating system built from scratch over 20 years, now fully open source. One ISO includes: firewall, VPN, web antivirus, URL filtering, SSL inspection, WAF, reverse proxy, load balancer and QoS. Free for any number of users. Optional paid support available. Source code: https://github.com/cacheguard/CacheGuard-OS Website: https://www.cacheguard.com/

Tired of seeing ads pop up on your Android device? You can take them all away with AdAway! AdAway is an open source ad blocker for Android that uses the hosts file and local vpn. It effectively keeps pesky ads at bay so you can continue using your Android device uninterrupted by constant ads. AdAway gives you the option to add custom sources of host files. It also lets you add custom rules for your whitelist, blocklist and rules for redirects, so your ad blocking is not just generic, but tailored specifically how you want it. AdAway is currently being used by dozens of Android users worldwide.

WireGuard Linux is the Linux kernel implementation of the WireGuard VPN protocol, providing high-performance encrypted networking directly within the Linux networking stack. The repository serves as a mirror of the official development tree and contains the kernel-side code that enables native WireGuard support on Linux systems. By operating inside the kernel rather than user space, the project achieves very low latency and high throughput, making it suitable for servers, embedded systems, and enterprise networking environments. WireGuard itself is designed to be a modern, streamlined VPN that uses state-of-the-art cryptography while remaining simpler and leaner than legacy solutions such as IPsec or OpenVPN. The Linux implementation integrates tightly with standard networking tools and interfaces, allowing administrators to manage tunnels using familiar workflows.

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).

OpenVPN Portable is openvpn and a modification of openvpn-gui, packaged with a PortableApps.com Launcher as a portable app, so you can take your vpn connection always with you. Unfortunately openvpn needs to install a network driver. This needs admin rights. OpenVPN Portable checks during the start process if the driver is installed. If not, the application asks for admin rights and installs it automatically.

P2PVPN is an easy to use VPN-Software. Users will be connected trough a P2P network, so no server is required.

OpenVPN v2.3.18 was the last version that officially supports Windows XP and Windows Server 2003. We lately had the need to use the newer version 2.5.4 of OpenVPN to support stronger data ciphers like AES-256-CBC. Therefore we decided to rebuild the whole package from the ground up to make it compatible with Windows XP and Windows Server 2003. The following article describes in detail how you can rebuild OpenVPN v2.5.4 for use on these older operating systems. The benefits of this new version include: - support of stronger data ciphers like AES-256-CBC - new TAP-Driver with a network speed of 1 GBit/s instead of 10 MBit/s - severe bug on Windows XP SP3 solved where we can't connect to the VPN server For more details visit https://openvpn-for-windows-xp.sourceforge.io/

WireGuard is an archived repository that preserves earlier monolithic development snapshots of the WireGuard project for historical and reference purposes. It reflects a previous stage in WireGuard’s evolution before the codebase was modularized into the modern multi-repository structure used today. The repository is valuable primarily for researchers, maintainers, and security analysts who want to study the protocol’s design history, implementation changes, or legacy behavior. Although not intended for production use, it provides insight into how WireGuard’s minimalist architecture and cryptographic approach matured over time. The project forms part of the broader WireGuard ecosystem, which focuses on delivering a simpler and faster VPN compared to legacy solutions. In practice, most users should rely on the actively maintained repositories, while this historical mirror serves educational and archival needs.

Rockhopper is IPsec/IKEv2-based VPN software for Linux. This software is interoperable with Windows 7, Windows 8 and Windows 10 VPN clients and it provides a handy AJAX-based Web console to manage Secure Virtual Ethernet(LAN), Routing-based VPN, Remote Access VPN and servers protected by IPsec. No kernel modules are needed. The ESP protocol stack is also implemented in user space.

Simple-VPN is an IPsec configuration tool. It abstracts the myriad of IPsec options and allows easy inter-operation of different implementations. Currently supports Racoon, Openswan and Strongswan.

SVPN provides an encrypted tunnel between two hosts, which in combination with IP forwarding enabled on one of the hosts can create a VPN.

A Layer 2 Tunneling Protocol VPN client/daemon for Linux and other POSIX-based OSs.

SigmaVPN is a light-weight, modular and secure VPN solution for UNIX-based systems.

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.

The port of VPN client cannot be changed under some kind of O.S (such as Win2000, WinXP). By using this proxy, you can specifie a VNP port. It uses the virtual ethernet driver of OpenVPN. For more, please visit www.simpleteam.com

Ncurses based tool for easily deploying IPsec tunnels using FreeSWAN (Linux only) Easy to configure a tunnel, simple options, user friendly interface

Hamachi-gui is a graphical front-end to Hamachi, a populare zero-configuration VPN client. Its tires to mimic the official Hamachi Windows GUI.

Implements a Windows NT VPN peer to Olaf Titz's CIPE VPN for Linux NOTE: The distribution must be downloaded from the home page