Software
VPN is designed to be a powerful tool for businesses and corporate networks to
allow workers to connect remotely, so there are a lot of setup and configuration
options available to tailor VPN to a network so when installing there will be a
bit of work required to get the service operational, but after that it will run
unattended.
For those with Windows Server a full VPN service is available
to install and run. As it is a fully featured version there will be more
configuration required to begin with and may become complicated as
miss-configurations wont present themselves and you could be left scratching
your head over them. That said when working it will be reliable and a service
that can be left alone to work when needed.
Windows Workstation operating systems do not have the ability
to function as a full VPN server, however with a bit of creative configuration
can be allowed to accept incoming connections from outside devices and give the
impression of a VPN service. The install process is a lot simpler but may not be
completely configurable to all needs, but still will function as a basic VPN
service.

If a Windows solution is out of reach or not suitable then there are 3rd party
options available for the Windows operating system, with the most commonly used
option being OpenVPN. This is an open source design that has
the power to provide a full VPN Server, mainly used for Linux it has a Windows
installer to make things easier. As with most Linux based software ported to
Windows configuration is done via editing text files rather than a GUI. However
with most open source products there is a large online community ready to give
advice and support.