3Com BETA, Руководство по началу работы

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Chapter 1. Introduction
What is a Telecommuting Module?
A Telecommuting Module is a device which processes traffic under the SIP protocol (see
RFC 3261). The Telecommuting Module receives SIP requests, processes them according to
the rules you have set up, and forwards them to the receiver.
The Telecommuting Module connects to an existing enterprise firewall through a DMZ port,
enabling the transmission of SIP-based communications without affecting firewall security.
SIP messages are then routed through the firewall to the private IP addresses of authorized
users on the internal network.
The Telecommuting Module can also be used as an extra gateway to the internal network
without connecting to the firewall, transmitting only SIP-based communications.
Configuration alternatives
The 3Com VCX IP Telecommuting Module can be connected to your network in three
different ways, depending on your needs.
Note that if the Standalone type is used, the interface which should receive traffic from the
outside must have a public IP address (no NAT).
For a DMZ or DMZ/LAN type which uses a private IP address on the interface connected
to the DMZ of the firewall, its corresponding public IP address must be entered on the
Interoperability page.
DMZ Configuration
Using this configuration, the Telecommuting Module is located on the DMZ of your firewall,
and connected to it with only one interface. The SIP traffic finds its way to the Telecommut-
ing Module using DNS or by setting the Telecommuting Module as an outbound proxy on
the clients.
This is the most secure configuration, since all traffic goes through both your firewall and
your Telecommuting Module. It is also the most flexible, since all networks connected to
any of your firewall’s interfaces can be SIP-enabled.
The drawback is that the SIP traffic will pass the firewall twice, which can decrease perfor-
mance.
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