ZyXEL p-662h-61 Guia Do Utilizador

Prestige 662HW Series User’s Guide

Chapter 14 Firewall Configuration

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2 What direction of traffic does the rule apply to (refer to the 

section)?

3 What IP services will be affected?

4 What computers on the LAN or DMZ are to be affected (if any)?

5 What 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.

1 Once the logic of the rule has been defined, it is critical to consider the security 

ramifications created by the rule:

2 Does this rule stop LAN users from accessing critical resources on the Internet? For 

example, if IRC is blocked, are there users that require this service?

3 Is it possible to modify the rule to be more specific? For example, if IRC is blocked for all 

users, will a rule that blocks just certain users be more effective?

4 Does a rule that allows Internet users access to resources on the LAN create a security 

vulnerability? For example, if FTP ports (TCP 20, 21) are allowed from the Internet to the 
LAN, Internet users may be able to connect to computers with running FTP servers.

5 Does this rule conflict with any existing rules?

6 Once these questions have been answered, adding rules is simply a matter of plugging the 

information into the correct fields in the web configurator screens.

Should the action be to Block or Forward?

Select the service from the Service scrolling list box. If the service is not listed, it is necessary 
to first define it. See the 

Predefined Services 

section

 

for more information on predefined 

services.

What is the connection’s source address; is it on the LAN, DMZ, WAN? Is it a single IP, a 
range of IPs or a subnet?

Note: “Block” means the firewall silently discards the packet.