Using DHCP Option 18 and Option 37 in Authentication Usernames for DHCPv6 Autosense VLANs
For DHCPv4, Option 82 has suboptions containing the ACI and ARI that are concatenated with the username during the authentication process for autosense (dynamic) VLANs. For DHCPv6, the relay agent uses Options 18 and Option 37 to convey the ACI and ARI, respectively. You can include these options in the username to generate unique usernames that identify subscribers for authentication in DHCPv6 dynamic VLANs.
A DHCPv6 Solicit message encapsulated with a Relay-Forward message header and one without the Relay-Forward message header are eligible for dynamic VLAN creation when you configure the DHCPv6 packet type for autosensing. Options 18 and Option 37 are provided in the Relay-Forward message header and are extracted only from this header and not from the options within the DHCPv6 Solicit message. In addition, if the DHCPv6 Solicit message is encapsulated in multiple Relay-Forward message headers, only the option values from the innermost Relay-Forward message header are used for username authentication. If these options are sent by the client or DHCPv6 relay agent, and if dynamic VLAN authentication is configured to use these options in the username, then the options are included in the username for authentication. If either of these options is not sent by the client or DHCPv6 relay agent, or if the dynamic VLAN authentication is not configured to use the option in the username, the username is constructed without the option.
To include Option 18 or Option 37 in the username for DHCPv6 dynamic VLANs, include the option-37 and option-18 statements at the [edit interfaces interface-name auto-configure vlan-ranges authentication username-include] hierarchy level. To include Options 18 or Option 37 in the username for stacked VLANs, include option-18 and option-37 statements at the [edit interfaces interface-name auto-configure stacked-vlan-ranges authentication username-include] hierarchy level.