3Com 4007, Implementation Manual, Page: 311 / 684

Important Considerations 311
Important
Considerations
■
After you create a packet filter, you must:
■
Assign the filter to the applicable ports
■
Assign the filter to the applicable transmit and receive paths
■
Define port groups, if needed
■
If you assign standard (hardware) filters on the receive multicast and
transmit multicast paths, they will be executed in software which can
slow the switch substantially. See “Standard Packet Filters” earlier in
this chapter for details.
■
Processing too many frames in software can affect performance on
the ports where custom filters are assigned. See “Custom Packet
Filters” earlier in this chapter for details.
■
Exit a filter as soon as possible. See “Implementing Sequential Tests in
a Packet Filter” later in this chapter for details.
Managing Packet
Filters
You can control and manage packet filters from the
bridge
packetFilter
menu of the Administration Console, as described in the
Switch 4007 Command Reference Guide .
■
Listing packet filters — You can list the packet filters that are
defined for the module. The display includes the filter identification,
filter name (if any), and filter assignments. Use the
bridge
packetfilter list
command.
■
Displaying packet filters — When you display the contents of a
single packet filter, you select the packet filter using the filter id
number that you see when you list the packet filters. The module
displays the packet filter instructions. Comments in the original packet
filter definition file are not displayed because they are not saved with
the packet filter. Use the
bridge packetfilter display
command.
■
Creating packet filters — You can create the standard (portGroup)
hardware filter or your own custom packet filters. Placing a filter on
the
receive path confines the packet to the segment it originated from
if it does not meet the forwarding criteria. Placing a filter on the
transmit path prohibits a packet from accessing certain segments
unless it meets the forwarding criteria. The module discards any
packet that does not meet the forwarding criteria. Use the
bridge
packetfilter create
command.