VPN software applications include clients, servers and utility programs. VPN software technology enables private communications over wireless / computer networks via a method called “tunneling.” The popular VPN software applications listed below are readily available for free download on the Internet.

1. Hamachi

Hamachi is free VPN software that uses a mediation server to establish peer-to-peer connections over UDP.

2. OpenVPN

OpenVPN is SSL-based open source VPN software. OpenVPN runs on Windows, Linux and Mac OS X operating systems.

3. Cisco VPN Client

The Cisco VPN client software supports IPSec connections to Cisco VPN concentrators. This VPN software application runs on Windows, Linux and Mac OS X.

4. Tinc VPN Daemon

The free Tinc VPN software enables virtual private networking via low-level daemon / network device configuration. Designed originally for Linux / Unix networks, Tinc also works on Windows computers.

5. FreeS/WAN

FreeS/WAN is an IPSec VPN software solution for Linux networks. Active development of FreeS/WAN has stopped, making this solution of interest mainly to students and researchers.
6. Zeroshell

Zeroshell is a small Linux distribution for servers and embedded devices aimed at providing the main network services a LAN requires. It is available in the form of Live CD or Compact Flash image and you can configure and administer it using your web browser.