ZyXEL Communications P-660HW-T1 User Manual

P-660H/HW/W-T Series User’ Guide

Chapter 11 Firewall Configuration

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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? “Block” means the firewall silently discards the 
packet.

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

for more information on predefined services.

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

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

This section describes examples for firewall rules for connections going from LAN to WAN 
and from WAN to LAN. 

LAN to LAN/ Router, WAN to WAN/ Router rules apply to packets coming in on the 
associated interface (LAN, WAN respectively). LAN to LAN/ Router means policies for 
LAN-to-Prestige (the policies for managing the Prestige through the LAN interface) and 
policies for LAN-to-LAN (the policies that control routing between two subnets on the LAN). 
Similarly, WAN to WAN/ Router polices apply in the same way to the WAN ports.

The default rule for LAN to WAN traffic is that all users on the LAN are allowed non-
restricted access to the WAN. When you configure a LAN to WAN rule, you in essence want 
to limit some or all users from accessing certain services on the WAN. WAN to LAN Rules