Chapter 17: DHCP Snooping Commands
318 Section III: Layer 2 Switching
ENABLE DHCPSNOOPING OPTION82
Syntax
enable dhcpsnooping option82
Parameters
None
Description
Use this command to set handling Relay Agent Information Option 82
enabled. Relay Agent Information Option 82 is enabled when DHCP
Snooping is enabled. When Relay Agent Information Option 82 is enabled,
the switch inserts the Relay Agent Information Option into DHCP and
BOOTP packets before forwarding them.
The Relay Agent Information Option 82 includes:
Remote-ID: the MAC address of the switch
Circuit-ID: the switch port that receives client packets and VLAN ID
of the port
Subscriber-ID: the value of the subscriberid parameter specified by
the SET DHCPSNOOPING PORT command
Here are the guidelines for Relay Agent Information Option 82:
Untrusted ports discard the DHCP and BOOTP packets that
include the Relay Agent Information Option.
Trusted ports forward the DHCP and BOOTP packets including the
Relay Agent Information Option.
When Relay Agent Information Option 82 is enabled, the switch
deletes the Relay Agent Information Option and forwards packets
back from the server to a client if the client is directly connected to
an untrusted port.
Confirmation Command
“SHOW DHCPSNOOPING” on page 328
Example
The following command sets Relay Agent Information Option 82 enabled:
Manager > enable dhcpsnooping option82
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