User`s guide

XSR User’s Guide 227
11
Configuring the Virtual Private
Network
VPN Overview
As it is most commonly defined, a Virtual Private Network (VPN) allows two
or more private networks to be connected over a publicly accessed network.
VPNs share some similarities with Wide Area Networks (WAN), but the key
feature of VPNs is their use of the Internet rather than reliance on expensive,
private leased lines. VPNs boast tighter security and encryption features as a
private network, while taking advantage of the economies of scale and
remote accessibility of large public networks.
Internet Security Issues
All communication over the Internet uses the Transmission Control
Protocol/Internet Protocol (TCP/IP) or User Datagram Protocol (UDP). They
convey packets from one computer to another through a variety of intermediate
computers and separate networks before they reach their destination.
The great flexibility of TCP/IP has led to its worldwide acceptance as the
basic Internet and intranet communications protocol. But, the fact that
TCP/IP allows traffic to pass through intermediate computers allows third
parties to interfere with communications in the following ways:
 Eavesdropping - Information remains intact, but its privacy is
compromised. For example, someone could learn your credit card
number, record a sensitive conversation, or intercept classified data.
 Tampering - Information in transit is changed or replaced and then sent
on to the recipient. For example, someone could alter an order for
goods or change a person's resume.