Anyone who has attempted to set up a virtual private network will be aware that it can be fraught with problems. OpenVPN is a comprehensive VPN tool which perfects the balance between ease of use and security which can be used to enable remote access on any scale and allow for communication between different networks.
Tunnelling of an IP subnet or virtual Ethernet adaptor over a single communication port means that the program is very firewall friendly, overcoming one of the problems that makes many VPN tools difficult to configure.
With security based on SSL you can use static, pre-shared keys or TLS-based dynamic key exchange, and real-time traffic analysis can be used to manage bandwidth usage between clients. When used for remote access or any other purpose, access control can be used to place restrictions on individual users or user groups.
Configuring a VPN is never going to be a simple process, but OpenVPN does help to make things easier. Thankfully this does not mean having to compromise on features or security, even though the program is available completely free of charge.
What's new in 2.4? See the release notes for information.
OpenVPN is not for the faint hearted, but anyone looking to make use of virtual private networks will find it hard to find a better tool.