ZyAIR G-2000 Plus User’s Guide

You may define additional rules and sets or modify existing ones but please exercise extreme caution in doing so.

Note: If you configure firewall rules without a good understanding of how they work, you might inadvertently introduce security risks to the firewall and to the protected network. Make sure you test your rules after you configure them.

For example, you may create rules to:

•Block certain types of traffic, such as IRC (Internet Relay Chat), from the LAN to the Internet.

•Allow certain types of traffic, such as Lotus Notes database synchronization, from specific hosts on the Internet to specific hosts on the LAN.

•Allow everyone except your competitors to access a Web server.

•Restrict use of certain protocols, such as Telnet, to authorized users on the LAN.

These custom rules work by comparing the Source IP address, Destination IP address and IP protocol type of network traffic to rules set by the administrator. Your customized rules take precedence and override the ZyAIR’s default rules.

15.3 Rule Logic Overview

Note: Study these points carefully before configuring rules.

15.3.1Rule Checklist

1State the intent of the rule. For example, This restricts all IRC access from the LAN to the Internet. Or, This allows a remote Lotus Notes server to synchronize over the Internet to an inside Notes server.

2Is the intent of the rule to forward or block traffic?

3What direction of traffic does the rule apply to (See “Types of Firewalls” on page 178)?

4What IP services will be affected?

5What computers on the LAN are to be affected (if any)?

6What computers on the Internet will be affected? The more specific, the better. For example, if traffic is being allowed from the Internet to the LAN, it is better to allow only certain machines on the Internet to access the LAN.

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Chapter 15 Firewall Screens