Chapter 9 - Virtual Private Networks - Netopia R2020 User Reference Manual

Virtual Private Networks 9-1
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V V V V i i i i r r r r t t t t u u u u a a a a l l l l P P P P r r r r i i i i v v v v a a a a t t t t e e e e N N N N e e e e t t t t w w w w o o o o r r r r k k k k s s s s
The Netopia R2020 Dual Analog Router offers both PPTP and ATMP Layer 2 tunneling support for Virtual 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 virtual private networks . Virtual , because they appear to be direct connections between the
calling and answering parties, even though they travel over the public wires and switches of the phone
company; private , because neither pair of calling and answering parties interacts with the other; and networks ,
because they exchange information.
Computers can do the same thing; it's called Virtual 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 encryption allowing the use of the public
Internet to look "virtually" 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.