User - Defined Packet Filtering; About User-Defined Packet Filtering; Designing A Packet Filter - 3Com LANPLEX 2500 Operation Manual

7
About
User-defined
Packet Filtering
Designing a
Packet Filter
U -
SER DEFINED
P F
ACKET
The LANplex system allows you to add a second layer of packet filtering on
top of the standard filtering provided by a traditional transparent bridge.
This chapter contains the following information on user-defined packet
filters:
A general description
How to use address groups and port groups in packet filters
Some packet filters
How to administer user-designed packet filters
User-defined packet filtering further restricts the packets to be forwarded
through the bridge. By taking advantage of this powerful feature, you can
improve network performance, provide additional security, or logically
segment your network to support virtual workgroups.
The packet filtering mechanism supported on the LANplex system is
flexible. You can define complex filters by combining many simple
comparisons. This flexibility allows you to use packet filters in several helpful
ways on your network.
You specify the packet filter using a packet filter language. This language
consists of operands and operators with which to compose your filters. The
language is described in detail in the LANplex® 2500 Administration Console
User Guide. Table 7-1 describes the two simplest operands in the packet
filter language.
ILTERING