Configuring DHCP Service
DHCP L2 Relay Configuration
User Guide
411
The following example shows how to enable DHCP L2 Relay globally and for VLAN 2:
Switch#configure
Switch(config)#ip dhcp l2relay
Switch(config)#ip dhcp l2relay vlan
2
Switch(config)#show ip dhcp l2relay
Global Status: Enable
VLAN ID: 2
Switch(config)#end
Switch#copy running-config startup-config
3.2.2 Configuring Option 82 for Ports
Follow these steps to configure Option 82:
Step 1
configure
Enter Global Configuration Mode.
Step 2
interface {
fastEthernet
port
| range fastEthernet
port-list
| gigabitEthernet
port
| range
gigabitEthernet
port-list
| ten-gigabitEthernet
port
| range ten-gigabitEthernet
port-list
}
Enter Interface Configuration Mode.
Step 3
ip dhcp l2relay information option
Enable the Option 82 feature on the port.
Step 4
ip dhcp l2relay information strategy
{
keep | replace | drop
}
Specify the operation for the switch to take when receiving DHCP packets that include the
Option 82 field.
keep
: The switch keeps the Option 82 field of the packets.
replace
: The switch replaces the Option 82 field of the packets with a new one. The switch
presets a default circuit ID and remote ID in TLV (Type, Length, and Value) format. You can
also configure the format to include Value only and customize the Value.
drop
: The switch discards the packets that include the Option 82 field.
Step 5
ip dhcp l2relay information format
{
normal | private
}
Specify the packet format for the sub-option fields of Option 82.
normal
: Indicates the fields consist of three parts: Type, Length, and Value (TLV).
private
: Indicates the fields consist of the value only.
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