User`s guide

Defining Filters and Firewalls
Example filters
6-12 Preliminary January 30, 1998 Pipeline User’s Guide
The source and destination Port Cmp and Port # parameters specify whether
to compare the protocol ports, which identify the application running over
TCP/IP. The comparison may match a protocol port number that is less-than,
greater-than, equal, or not-equal.
8
Set the TCP Estab parameter.
The TCP Estab parameter can be set to match a packet only if a TCP session
is already established.
Example filters
This section provides a step-by-step examples of defining filters. It shows how to
specify both generic and IP filter conditions.
This section shows how to create Filter profiles. Some sites modify the
predefined call filters to make them more full-featured for the types of packets
commonly seen at that site. See “Working with predefined call filters” on page 6-
21 for details.
An example generic filter to handle AppleTalk broadcasts
This section shows how to define a generic data filter whose purpose is to prevent
local AppleTalk AEP and NBP traffic from going across the WAN. The data filter
first defines the types of packets that should not be filtered:
• AppleTalk Address Resolution Protocol (AARP) packets
• AppleTalk packets that are not addressed to the AppleTalk multicast address,
such as regular traffic related to an actual AppleTalk File Server connection
• All non-AppleTalk traffic
The filter then defines the packets that should be dropped:
• AppleTalk Echo Protocol (AEP)
• Name Binding Protocol (NBP)
To define a generic data filter:
1
Select an unnamed Filter profile in the Filters menu and press Enter.
For example, select 20-403.