Disabling or re-enabling DHCP option 82 processing on an interface

By default, when DHCP option 82 is enabled on a VLAN, DHCP packets received on all member ports of the VLAN are subject to DHCP option 82 processing. You can disable or re-enable this processing on one or more member ports of the VLAN.

Option 82 is automatically enabled when you enable DHCP snooping on the VLAN.
  1. To disable Option 82, enter global configuration mode by issuing the configure terminal command.
    device# configure terminal
  2. Enter interface configuration mode.
    device(config)# interface ethernet 1/1/4
  3. Disable DHCP option 82 on the interface.
    device(config-if-e1000-1/1/4)# no dhcp snooping relay information
  4. Re-enable DHCP option 82, as required at the interface configuration level.
    device(config-if-e1000-1/1/4)# dhcp snooping relay information
  5. You can also re-enable DHCP option 82 after it has been disabled on a range of ports. First, specify the range of ports at the global configuration level and then enter the dhcp snooping relay information command.
    device(config)# interface ethernet 1/1/1 to 1/1/5
    device(config-mif-1/1/1-1/1/5)# dhcp snooping relay information

The following example disables DHCP option 82.

device# configure terminal
device(config)# interface ethernet 1/1/4
device(config-if-e1000-1/1/4)# no dhcp snooping relay information

The following example re-enables DHCP option 82 at the interface configuration level.

device# configure terminal
device(config)# interface ethernet 1/1/4
device(config-if-e1000-1/1/4)# dhcp snooping relay information

The following example re-enables DHCP option 82 on a range of ports.

device(config)# interface ethernet 1/1/1 to 1/1/5
device(config-mif-1/1/1-1/1/5)# dhcp snooping relay information