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15.1 IPSec VPN Overview
A virtual private network (VPN) provides secure communications between sites without the
expense of leased site-to-site lines. A secure VPN is a combination of tunneling, encryption,
authentication, access control and auditing. It is used to transport traffic over the Internet or
any insecure network that uses TCP/IP for communication.
Internet Protocol Security (IPSec) is a standards-based VPN that offers flexible solutions for
secure data communications across a public network like the Internet. IPSec is built around a
number of standardized cryptographic techniques to provide confidentiality, data integrity and
authentication at the IP layer.
The following figure provides one perspective of a VPN tunnel.
Figure 102 IPSec VPN: Overview
The VPN tunnel connects the NBG460N (X) and the remote IPSec router (Y). These routers
then connect the local network (A) and remote network (B).
15.1.1 What You Can Do in the IPSec VPN Screens
Use the General Screen
VPN rules (tunnels).
Use the SA Monitor Screen
connections.
NBG460N User's Guide
(Section 15.2 on page
167) to display and manage the NBG460N's
(Section 15.3 on page
15
IPSec VPN
183) to display and manage active VPN
165