Disabling or Re-enabling DHCP Option 82 Processing on all VLAN Member Ports

You can disable or re-enable DHCP option 82 processing globally, and disable and re-enable as necessary on specified VLANs. The following task disables DHCP option 82 globally. IP DHCP snooping is then enabled for VLANs 100, 200, and 300, but DHCP option 82 is not automatically enabled because it has been disabled globally. DHCP option 82 is then re-enabled on all ports for VLAN 100.
  1. Enter global configuration mode. 
    device# configure terminal
  2. Use the ip dhcp snooping relay information disable command to disable DHCP option 82 globally for all VLANs. 
    device(config)# ip dhcp snooping relay information disable
  3. Use the ip dhcp snooping command, specifying VLANs as required, to configure DHCP snooping for the specified VLANs. 
    device(config)# ip dhcp snooping vlan 100 to 300
  4. Enable DHCP option 82 on all ports for VLAN 100. 
    device(config)# no ip dhcp snooping relay information disable vlan 100

The following example disables DHCP option 82 globally and enables IP DHCP snooping for VLANs 100 through 300. DHCP option 82 is then enables on all ports for VLAN 100. 

device# configure terminal
device(config)# ip dhcp snooping relay information disable
device(config)# ip dhcp snooping vlan 100 to 300
device(config)# no ip dhcp snooping relay information disable vlan 100

The following example automatically enables DHCP option 82 for VLANs 100, 200, and 300. It then disables DHCP option 82 globally for all ports on VLAN 100. 

device# configure terminal
device(config)# ip dhcp snooping vlan 100 to 300
device(config)# ip dhcp snooping relay information disable vlan 100

The following example disables DHCP option 82 globally for all VLANs and ports in the specified range of VLANs. 

device# configure terminal
device(config)# ip dhcp snooping vlan 100 to 300
device(config)# ip dhcp snooping relay information disable
Warning - DHCP snooping relay information will be disabled on all port(s) & VLAN(s). You can enable it on individual ports/VLAN(s)
device(config)#

The following example disables DHCP option 82 globally for all ports and VLANs and re-enables it for VLAN 100. 

device# configure terminal
device(config)# ip dhcp snooping vlan 100 to 500
device(config)# ip dhcp snooping relay information disable
Warning - DHCP snooping relay information will be disabled on all port(s) & VLAN(s). You can enable it on individual ports/VLAN(s)
device(config)# no ip dhcp snooping relay information disable vlan 100

The following example enables DHCP option 82 for a specified range of VLANs. 

device# configure terminal
device(config)# ip dhcp snooping relay information disable vlan 11 to 15
Parent topic: DHCP Option 82 Configuration