Netopia 4541, 4542 manual Adding filters to a filter set, Netopia Router

11-14 User’s Reference Guide

Adding filters to a filter set

There are two kinds of filters you can add to a filter set: input and output. Input filters check packets received from the Internet, destined for your network. Output filters check packets transmitted from your network to the Internet.

WAN

packet

input filter

packet

output filter

The Netopia Router

LAN

Packets in the Netopia 4541/4542 pass through an input filter if they originate in the WAN and through an output filter if they’re being sent out to the WAN.

The process for adding input and output filters is exactly the same. The main difference between the two involves their reference to source and destination. From the perspective of an input filter, your local network is the destination of the packets it checks, and the remote network is their source. From the perspective of an output filter, your local network is the source of the packets, and the remote network is their destination.

Type of filter	Source means	Destination means
Input filter	The remote network	The local network
Output filter	The local network	The remote network

To add a filter, select Display/Change Filter Set in the Filter Set screen. From the pop-up menu, select the filter set to which you will add a filter. The Display/Change Filter Set screen appears.