Preventing The Forwarding Of Dynamically Learned Stations - Cisco WS-C3550-12G Software Configuration Manual

Chapter 26 Configuring Fallback Bridging
This example shows how to create bridge group 10, specify the VLAN-bridge STP to run in the bridge
group, and assign an interface to the bridge group:
Switch(config)# bridge 10 protocol vlan-bridge
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# no switchport
Switch(config-if)# bridge-group 10

Preventing the Forwarding of Dynamically Learned Stations

By default, the switch forwards any frames for stations that it has dynamically learned. By disabling this
activity, the switch only forwards frames whose addresses have been statically configured into the
forwarding cache.
Beginning in privileged EXEC mode, follow these steps to prevent the switch from forwarding frames
for stations that it has dynamically learned:
Command
Step 1
configure terminal
Step 2
no bridge bridge-group acquire
Step 3
end
Step 4
show running-config
Step 5 copy running-config startup-config
To cause the switch to forward frames to stations that it has dynamically learned, use the bridge
bridge-group acquire global configuration command.
This example shows how to prevent the switch from forwarding frames for stations that it has
dynamically learned in bridge group 10:
Switch(config)# no bridge 10 acquire
78-11194-03
Purpose
Enter global configuration mode.
Enable the switch to stop forwarding any frames for stations that it has
dynamically learned through the discovery process and to limit frame
forwarding to statically configured stations.
The switch filters all frames except those whose destined-to addresses
have been statically configured into the forwarding cache. To configure
a static address, use the bridge bridge-group address mac-address
{forward | discard} global configuration command.
For bridge-group, specify the bridge group number. The range is 1
to 255.
Return to privileged EXEC mode.
Verify your entry.
(Optional) Save your entry in the configuration file.
Catalyst 3550 Multilayer Switch Software Configuration Guide
Configuring Fallback Bridging
26-5