VPN literal translation is a virtual private channel, which is a tunnel for secure data transmission between enterprises or between individuals and companies. OpenVPN is undoubtedly the pioneer of open source VPN under Linux, providing good performance and friendly user GUI. 
It makes extensive use of the SSL V3 / tlsv1 protocol function library in the OpenSSL encryption library. 
At present, OpenVPN can run on Solaris, Linux, OpenBSD, FreeBSD, NetBSD, Mac OS X, Microsoft Windows, Android and IOS, and contains many security functions. It is not a web-based VPN software, nor is it compatible with IPSec and other VPN packages.