Инструкции По Установке для Nortel 100

20 Chapter 1 Introduction

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Before you install the Instant Internet unit, you should understand your network 
environment and how the unit functions in the network.

Instant Internet can function in your network in three ways. It can:

•

Provide security – You can isolate your network from the Internet to help 
ensure network security. You do this for three reasons:

— To prevent Internet users from outside your organization from seeing 

internal IP addresses.

— To protect your network from being accessed by intruders or hackers.

— To permit remote LANs to communicate with your LAN over a virtual 

private network (VPN) using IP security (IPsec).

•

Control Internet access – You can restrict your users’ access by date and 
time, and you can restrict access to certain sites or news groups.

•

Ease administration – Instant Internet allows you to adopt the users and 
groups you are already using from your directory services.

For security purposes, on an IP network, you may want to isolate your network 
from the Internet. You can isolate your network from the Internet by configuring 
the network workstations to go through a router before accessing the Internet. 
However, using a router to isolate the LAN can be very time-consuming to set up 
and maintain because each LAN user must have a “legal” IP address and be 
protected from hackers. Instant Internet, on the other hand, makes it easy to isolate 
your IP network from the Internet by using address translation to translate illegal 
(reserved private) LAN workstation IP addresses into legal IP addresses.

You can also use IP security (IPsec) to create a virtual private network (VPN). 
A VPN is a special type of connection that permits remote users or LANs to 
communicate with another LAN over a public network, such as the Internet. 
When you set up a VPN, you are essentially using a public network as your own 
private, secure network. 

On IP networks with IP workstations, there is virtually no limit to the number of 
application sessions (instances) that can access the Instant Internet unit.