Netopia R2020 사용자 설명서

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Virtual Private Networks   9-1
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The Netopia R2020 Dual Analog Router offers both PPTP and ATMP Layer 2 tunneling suppor t for Vir tual Private 
Networks (VPN) as a component of a connection profile. 
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When you make a long distance telephone call from your home to a relative far away, you are creating a private 
network. You can hold a conversation, and exchange information about the happenings on opposite sides of the 
state, or the continent, that you are mutually interested in. When your next door neighbor picks up the phone to 
call her daughter at college, at the same time you are talking to your relatives, your calls don't overlap, but each 
is separate and private. Neither house has a direct wire to the places they call. Both share the same lines on 
the telephone poles (or underground) on the street.
These calls are 
vir tual private networks. Vir tual, because they appear to be direct connections between the 
calling and answering par ties, even though they travel over the public wires and switches of the phone 
company; 
private, because neither pair of calling and answering par ties interacts with the other; and networks, 
because they exchange information.
Computers can do the same thing; it's called Vir tual Private Networks (VPNs). Equipped with Netopia Routers 
running the version 4.4 firmware, a single computer or private network (LAN) can establish a private connection 
with another computer or private network over the public network (Internet).
The Netopia Router can be used in VPNs either to initiate the connection or to answer it. When used in this way, 
the routers are said to be 
tunnelling through the public network (Internet). The advantages are that, like your 
long distance phone call, you don't need a direct line between one computer or LAN and the other, but use the 
local connections, making it much cheaper; and the information you exchange through your tunnel is private and 
secure.
Tunneling is a process of creating a private path between a remote user or private network and another private 
network over some intermediate network, such as the IP-based Internet. A VPN allows remote offices or 
employees access to your internal business LAN through means of encr yption allowing the use of the public 
Internet to look “vir tually” like a private secure network. When two networks communicate with each other 
through a network based on the Internet Protocol, they are said to be 
tunneling through the IP network.