Using the set dhcp relay agent sub-option Command to Enable Option 82 Suboption Support

Note: We recommend that you use the set dhcp relay agent sub-option command for new option 82 suboption configurations. However, JunosE Software continues to support the set dhcp relay agent command, with option 82 suboptions, to provide backward-compatibility for existing scripts.

You use the set dhcp relay agent sub-option command to enable support for a specific DHCP relay agent option 82 suboption—Agent Circuit ID (suboption 1), Agent Remote ID (suboption 2), and Vendor-Specific (suboption 9). When you issue this command, the router adds DHCP relay agent information suboption 1 to every packet it relays from a DHCP client to a DHCP server. The Agent Circuit ID suboption identifies the interface on which DHCP packets are received. When the packets are received on a LAG interface, the router clearly identifies the interface.

The suboptions include information from the DHCP relay agent that the DHCP server can use to implement parameter assignment policies. The DHCP server echoes the suboptions when it replies to the DHCP client, but the DHCP relay strips the suboptions before relaying the packets to the client.

The Agent Circuit ID suboption identifies the interface on which the DHCP packets are received. This suboption contains the following information, based on interface type:

The Agent Remote ID suboption contains a value only when (1) the interface is a dynamic ATM interface and (2) the subscriber command is used to configure a username and domain name for the interface. If both conditions are met, the suboption contains a string with the username and domain name in the format: username@domainname.

The Vendor-Specific suboption contains a value that includes a JunosE data field. You can configure the data field to support one or both of the following values:

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