ZyXEL Communications 2WG - Manual (Page 246)

ZyWALL 2WG Support Notes
All contents copyright (c) 2006 ZyXEL Communications Corporation.
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policy, Gateway_1. In this case, this will be counted as two VPN tunnels.
F02. What is VPN?
A VPN gives users a secure link to access corporate network over the Internet or other public or private
networks without the expense of lease lines. A secure VPN is a combination of tunneling, encryption,
authentication, access control and auditing technologies/services used to transport traffic over the Internet
or any insecure network that uses the TCP/IP protocol suite for communication.
F03. Why do I need VPN?
There are some reasons to use a VPN. The most common reasons are because of security and cost.
Security
1). Authentication
With authentication, VPN receiver can verify the source of packets and guarantee the data integrity.
2). Encryption
With encryption, VPN guarantees the confidentiality of the original user data.
Cost
1). Cut long distance phone charges
Because users typically dial the their local ISP for VPN, thus, long distance phone charge is reduced than
making a long direct connection to the remote office.
2).Reducing number of access lines
Many companies pay monthly charges for two types access lines: (1) high-speed links for their Internet
access and (2) frame relay, ISDN Primary Rate Interface or T1 lines to carry data. A VPN may allow a