Virtual private networks (vpns), Overview, Chapter 10 — virtual private networks (vpns) -1 – Netopia 4541 User Manual
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Virtual Private Networks (VPNs) 10-1
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The Netopia 4541/4542 offers IPsec, PPTP, and ATMP tunneling suppor t for Vir tual Private Networks (VPN).
The following topics are covered in this chapter:
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"About PPTP Tunnels" on page 10-3
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"About IPsec Tunnels" on page 10-7
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"About ATMP Tunnels" on page 10-12
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"Encr yption Suppor t" on page 10-15
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"ATMP/PPTP Default Profile" on page 10-16
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"Dial-Up Networking for VPN" on page 10-18
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"Installing the VPN Client" on page 10-21
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"Allowing VPNs through a Firewall" on page 10-23
Overview
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 a Netopia
4541/4542, 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 4541/4542 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.