ZyXEL Communications PMG5318-B20A, User Manual

Page: 135 / 168

Chapter 15 Firewall
PMG5318-B20A User’s Guide
135
15.4 Firewall Technical Reference
This section provides some technical background information about the topics covered in this
chapter.
15.4.1 Firewall Rules Overview
Your customized rules take precedence and override the GPON Device’s default settings. The GPON
Device checks the source IP address, destination IP address and IP protocol type of network traffic
against the firewall rules (in the order you list them). When the traffic matches a rule, the GPON
Device takes the action specified in the rule.
Firewall rules are grouped based on the direction of travel of packets to which they apply:
Note: The LAN includes both the LAN port and the WLAN.
By default, the GPON Device’s stateful packet inspection allows packets traveling in the following
directions:
• LAN to WAN
These rules specify which computers on the LAN can access which computers or services on the
WAN.
By default, the GPON 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.
Note: 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.
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.
Cancel Click this to restore your previously saved settings.
Delete Click this to delete the current rule.
Table 52
Security > Firewall > Rules: Edit: Edit Customized Services: Config
LABEL DESCRIPTION
• WAN to LAN
• LAN to WAN