Netgear FVM318 – Cable and DSL ProSafe Wireless VPN Security Firewall 참조 매뉴얼

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Reference Manual for the Model FVM318 Cable/DSL ProSafe Wireless VPN Security Firewall
Network, Routing, Firewall, and Wireless Basics
B-21
 
How Does VPN Work?
A VPN can be thought of as a secure tunnel passing through the Internet, connecting two devices 
such as a PC or router, which form the two tunnel endpoints. At one endpoint, data is encapsulated 
and encrypted, then transmitted through the Internet. At the far endpoint, the data is received, 
unencapsulated and decrypted. Although the data may pass through several Internet routers 
between the endpoints, the encapsulation and encryption forms a virtual “tunnel” for the data. 
Figure 8-6: VPN overview
The tunnel endpoint device, which encodes or decodes the data, can either be a PC running VPN 
client software or a VPN-enabled router or server. Several software standards exist for VPN data 
encapsulation and encryption, such as PPTP and IPSec. Your FVM318 firewall uses both PPTP 
and IPSec.
To set up a VPN connection, you must configure each endpoint with specific identification and 
connection information describing the other endpoint. This set of configuration information 
defines a security association (SA) between the two points. 
IKE: Managing and Exchanging Keys
IKE (Internet Key Exchange protocol) is the protocol used to perform key exchange between 
IPSec devices. In order to initiate communication, the following tasks need to be done:
Negotiate security protocols, encryption algorithms and keys with all communicating peers
DATA PACKET
ENCRYPTION AND ENCAPSULATION
UNENCAPSULATION AND DECRYPTION
INTERNET
TRANSMISSION
VIA INTERNET
DATA PACKET