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ZyWALL 110/310/1100 Series User’s Guide
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IPSec VPN
20.1 Virtual Private Networks (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.
IPSec VPN
Internet Protocol Security (IPSec) VPN connects IPSec routers or remote users using IPSec client
software. This standards-based VPN offers flexible solutions for secure data communications across
a public network. IPSec is built around a number of standardized cryptographic techniques to
provide confidentiality, data integrity and authentication at the IP layer. The ZyWALL can also
combine multiple IPSec VPN connections into one secure network. Here local ZyWALL X uses an
IPSec VPN tunnel to remote (peer) ZyWALL Y to connect the local (A) and remote (B) networks.
Figure 174
IPSec VPN Example
SSL VPN
SSL VPN uses remote users’ web browsers to provide the easiest-to-use of the ZyWALL’s VPN
solutions. A user just browses to the ZyWALL’s web address and enters his user name and
password to securely connect to the ZyWALL’s network. Remote users do not need to configure
security settings. Here a user uses his browser to securely connect to network resources in the
same way as if he were part of the internal network. See
Chapter 21 on page 317 for more on SSL
VPN.