ZyXEL Communications P-2802H-I Series, User Manual

Page: 157 / 418

Chapter 11 Firewalls
P-2802H(W)(L)-I Series User’s Guide
157
• LAN to WAN
These rules specify which computers on the LAN can access which computers or services
on the WAN.
By default, the ZyXEL Device’s stateful packet inspection drops packets traveling in the
following directions:
• WAN to LAN
These rules specify which computers on the WAN can access which computers or services
on the LAN.
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You also need to configure NAT port forwarding (or full featured NAT address
mapping rules) to allow computers on the WAN to access devices on the LAN.
• WAN to WAN/ Router
By default the ZyXEL Device stops computers on the WAN from managing the ZyXEL
Device or using the ZyXEL Device as a gateway to communicate with other computers on
the WAN. You could configure one of these rules to allow a WAN computer to manage the
ZyXEL Device.
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You also need to configure the remote management settings to allow a WAN
computer to manage the ZyXEL Device.
You may define additional rules and sets or modify existing ones but please exercise extreme
caution in doing so.
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 ZyXEL Device’s default rules.