ip broadcast-zero

Enables the Layer 3 switch for zero-based IP subnet broadcasts in addition to ones-based IP subnet broadcasts.
Syntax
ip broadcast-zero
no ip broadcast-zero
Command Default

By default, the Layer 3 switch treats IP packets with all ones in the host portion of the address as IP broadcast packets.

Modes

Global configuration mode

Usage Guidelines

Most IP hosts are configured to receive IP subnet broadcast packets with all ones in the host portion of the address. However, some older IP hosts instead expect IP subnet broadcast packets that have all zeros instead of all ones in the host portion of the address. To accommodate this type of host, you can enable the Layer 3 switch to treat IP packets with all zeros in the host portion of the destination IP address as broadcast packets.

When you enable the Layer 3 switch for zero-based subnet broadcasts, the Layer 3 switch still treats IP packets with all ones the host portion as IP subnet broadcasts too. Thus, the Layer 3 switch can be configured to support all ones only (the default) or all ones and all zeroes.

Note: This feature applies only to IP subnet broadcasts, not to local network broadcasts. The local network broadcast address is still expected to be all ones.

You must save the configuration and reload the software to place this configuration change into effect.

The no form of the command disablesthe Layer 3 switch for zero-based IP subnet broadcasts in addition to ones-based IP subnet broadcasts.

Examples

The following example enables the Layer 3 switch for zero-based IP subnet broadcasts in addition to ones-based IP subnet broadcasts. 

device(config)# ip broadcast-zero
device(config)# write memory
device(config)# end
device# reload
Parent topic: Commands I