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option-18 (DHCPv6 Snooping)


Hierarchy Level


Configure the DHCPv6 Relay Agent Interface ID option (option 18) to insert information in DHCPv6 requests from clients before forwarding them to a DHCPv6 server. Option 18 provides information about the port on which the request was received, which the server can use to assign IP addresses, prefixes, and other configuration parameters for the client.

When option 18 is configured, a unique interface ID is inserted into the DHCPv6 packet headers. Suboptions can be configured to include a prefix with the interface ID or to change the type of information used to identify the interface. The default fields included in option 18 are the Juniper Enterprise ID, VLAN, and MAC address of the interface.

Option 18 is the DHCPv6 equivalent of the circuit-id sub-option of DHCP option 82.


DHCPv6 packets that already contain option 18 information when received from a client are dropped by the switch.



Use the MAC address of the interface in the DHCPv6 interface ID.

use-string string

Use a custom string in the DHCPv6 interface ID.

The remaining statements are explained separately.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 14.1X53-D10.