"The Network File System (NFS) is a standard protocol for
sharing file services with Linux and Unix computers. It is a
distributed file system that enables local access to remote disks
and file systems and is based on the client\server architecture.
Although easy to configure, it is typically used only to transfer
data over an intranet or LAN because of its transparency and
security potholes when exposed to the risks of the Internet.
However, it still can be employed--without compromising
security--to share files over the Internet by configuring it to run
on a Virtual Private Network (VPN) connection. This article will
show you how to set up NFS to run over a CIPE-VPN connection
between two Linux systems..."