Avocent Access Router Cyclades-PR2000 - Manual (Page 115)

Cyclades-PR2000
Chapter 14 - Virtual Private Network Configuration 115
CHAPTER 14 VIRTUAL PRIVATE NETWORK CONFIGURATION
The Virtual Private Network utility can be used on any link using IP routing. It is used to provide greater
security between two or more networks connected through a public communications network. The basic
concepts are presented in Figure 14.1. An IP datagram is sent by a device on the LAN. The message arrives
at the router. The router has two tables. One with all the IP addresses contained in the Local Security Network
and another with all the IP addresses in the Remote Security Networks. If the source IP address is contained
in the Local Security Network list and the destination IP address is contained in the Remote Security Network
list, the message is encrypted and encapsulated. The only destination address is that for the remote gateway
(defined in the Remote Security Network list). Upon arrival at the remote gateway, the packet is unwrapped
and sent to its destination.
...... ...... ...... ...... ...... ....
PC
PC
Message Message
Message
PR3000 PR4000 Header
Header with destination:
remote security gateway
IP Address
IP Datagram
sent by user
Conversion
performed by Router
with Cyclades’ VPN
As sent by
local Gateway
As received by
remote Gateway
Source IP Address
Destination IP Address
IP Options and Data
Encrypted IP Datagram
Header with destination:
remote security gateway
IP Address
Encrypted IP Datagram
Message
Header
Source IP Address
Destination IP Address
IP Options and Data
Local
Gateway
Remote
Gateway
Public
Network
FIGURE 14.1 CONVERSION PERFORMED BY CYCLADES’ VIRTUAL PRIVATE NETWORK UTILITY