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Cisco ME 3400 EthernetAccess Switch SoftwareConfiguration Guide
78-17058-01
Chapter32 Configuring IP Unicast Routing Configuring IP Addressing
Use the no ip helper-address interface configuration command to disable the forwarding of broadcast
packets to specific addresses. Use the no ip forward-protocol global configuration command to remove
a protocol or port.
Establishing an IP Broadcast Address
The most popular IP broadcast address (and the default) is an add re ss cons isti ng o f all on es
(255.255.255.255). However, the switch can be configured to generate any form of I P broadcast address.
Beginning in privileged EXEC mode, follow these steps to set the IP broadcast address on an interface:
To restore the default IP broadcast address, use the no ip broadcast-address interface configuration
command.
Flooding IP Broadcasts
You can allow IP broadcasts to be flooded throughout your internetwork in a controlled fashion by using
the database created by the bridging STP. Using this feature also prevents loops. To support this
capability, bridging must be configured on each interface that is to participa te in the flooding. If bridging
is not configured on an interface, it still can receive broadcasts. However, the interface never forwards
broadcasts it receives, and the router never uses that interface to send broadcasts received on a
different interface.
Packets that are forwarded to a single network address using the IP helper-address mechanism can be
flooded. Only one copy of the packet is sent on each network segment.
Step8 show ip interface [interface-id]
or
show running-config
Verify the configuration on the interface or all interfaces.
Step9 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Enter interface configuration mode, and specify the interface to
configure.
Step3 no shutdown Enable the interface if necessary. By default, UNIs are disabled
and NNIs are enabled.
Step4 ip broadcast-address ip-address Enter a broadcast address different from the default, for example
128.1.255.255.
Step5 end Return to privileged EXEC mode.
Step6 show ip interface [interface-id] Verify the broadcast address on the interface or all interfaces.
Step7 copy running-config startup-config (Optional) Save your entries in the configuration file.