ZyXEL Communications 70 Series User Manual

ZyWALL 5/35/70 Series User’s Guide

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Chapter 11 Firewall Screens

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, DMZ, WLAN or 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, DMZ, WLAN or 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. Rules for the WLAN or DMZ work in a similar fashion.

LAN to LAN/ZyWALL, WAN to WAN/ZyWALL, WLAN to WLAN/ZyWALL and DMZ to 
DMZ/ZyWALL rules apply to packets coming in on the associated interface (LAN, WAN, 
WLAN, or DMZ respectively). LAN to LAN/ZyWALL means policies for LAN-to-ZyWALL 
(the policies for managing the ZyWALL 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/ZyWALL, WLAN to WLAN/ZyWALL and DMZ to DMZ/ZyWALL polices apply in 
the same way to the WAN, WLAN and DMZ 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. See the following 
figure.