13-14 User’s Reference Guide
Input and output filters—source and destination
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 R5000 Series Router 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 |
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Input filter | The remote network | The local network |
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Output filter | The local network | The remote network |
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Adding filters to a filter set
In this section you’ll learn how to add an input filter to a filter set. Adding an output filter works exactly the same way, providing you keep the different source and destination perspectives in mind.
To add an input filter, navigate to the Display/Change Filter Set screen and select Display/Change Filter Set.
Main
Menu
System
Configuration
Filter Sets
Display/Change
Filter Set
A popup menu displays a list of the filter sets you have created.
