ABSTRACT
The next few subsections of this entry describe in more
detail common VPN situations.
Secure Remote User Access over the Internet.While
maintaining privacy of information, VPNs provide remote
access to enterprise resources over the public Internet.
A VPN that is used to connect a remote user to an enter-
prise intranet is shown in Fig. 2. The user first calls a local
ISP Network Access Server (NAS) phone number, rather
than making a leased-line, long-distance (or 1-800) call to
an enterprise or outsourced NAS. The VPN software cre-
ates a virtual private network between the dial-up user and
the enterprise VPN server across the Internet using the
local connection to the ISP.
