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Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
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Chapter 33 Configuring Layer 3 Protocol Filtering
Default Layer 3 Protocol Filtering Configuration
For example, if a host that supports both IP and Internetwork Packet Exchange (IPX) is connected to a
switch port configured as
auto
for IPX, but the host is transmitting only IP traffic, the port to which the
host is connected will not forward any IPX flood traffic to the host. However, if the host sends an IPX
packet, the supervisor engine software detects the protocol traffic and the port is added to the IPX group,
allowing the port to receive IPX flood traffic. If the host stops sending IPX traffic for more than
60 minutes, the port is removed from the IPX protocol group.
By default, ports are configured to
on
for the IP protocol group. Typically, you should only configure a
port to
auto
for IP if there is a directly connected end station out the port. The default port configuration
for IPX and Group is
auto
.
With Layer 3 protocol filtering enabled, ports are identified on a protocol basis. A port can be a member
of one or more of the protocol groups. Flood traffic for each protocol group is forwarded out a port only
if that port belongs to the appropriate protocol group.
Packets are classified into the following protocol groups:
•
IP
•
IPX
•
AppleTalk, DECnet, and Banyan VINES (
group
mode)
•
Packets not belonging to any of these protocols
Default Layer 3 Protocol Filtering Configuration
Table 33-1
shows the default Layer 3 protocol filtering configuration.
Configuring Layer 3 Protocol Filtering
These sections describe how to configure Layer 3 protocol filtering on Ethernet-type VLANs and on any
type of Ethernet port:
•
Enabling Layer 3 Protocol Filtering, page 33-3
•
Disabling Layer 3 Protocol Filtering, page 33-3
Table 33-1 Layer 3 Protocol Filtering Default Configuration
Feature
Default Value
Layer 3 protocol filtering
Disabled
ip
mode
on
ipx
mode
auto
group
mode
auto
