Firewall Rule Direction - ZyXEL Communications P-870HW-I Series User Manual

P-870HW-I1 User's Guide
• The DSL port connects to the Internet.
• The LAN (Local Area Network) ports attach to a network of computers, which needs
security from the outside world. These computers will have access to Internet services
such as e-mail, FTP, and the World Wide Web. However, "inbound access" will not be
allowed unless you configure remote management or create a firewall rule to allow a
remote host to use a specific service.

11.1.3 Firewall Rule Direction

Firewall rules are grouped based on the direction of travel of packets to which they apply:
• LAN to LAN/ Router
• LAN to WAN
Note: The LAN includes both the LAN port and the WLAN.
By default, the ZyXEL Device's stateful packet inspection allows packets traveling in the
following directions:
• LAN to LAN/ Router
This allows computers on the LAN to manage the ZyXEL Device and communicate
between networks or subnets connected to the LAN interface.
• LAN to WAN
By default, the ZyXEL Device's stateful packet inspection drops packets traveling in the
following directions:
• WAN to LAN
• WAN to WAN/ Router
This prevents computers on the WAN from using the ZyXEL Device as a gateway to
communicate with other computers on the WAN and/or managing the ZyXEL Device.
You may define additional rules and sets or modify existing ones but please exercise
extreme caution in doing so.
Note: If you configure firewall rules without a good understanding of how they work,
you might inadvertently introduce security risks to the firewall and to the
protected network. Make sure you test your rules after you configure them.
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.
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• WAN to LAN
• WAN to WAN/ Router
Chapter 11 Firewalls