DHCP relay agent support for Option 82
Option 82 records location information about the DHCP client, letting the administrator locate the DHCP client for security control and accounting purposes. For more information, see "DHCP overview."
If the DHCP relay agent supports Option 82, it handles a client's request according to the contents defined in Option 82, if any. The handling strategies are described in Table 3.
If a reply returned by the DHCP server contains Option 82, the DHCP relay agent removes the Option 82 before forwarding the reply to the client.
Table 3: Handling strategies of the DHCP relay agent
If a client's requesting message has… | Handling strategy | Padding format | The DHCP relay agent will… |
|---|---|---|---|
Option 82 | Drop | Random | Drop the message. |
Keep | Random | Forward the message without changing Option 82. | |
Replace | normal | Forward the message after replacing the original Option 82 with the Option 82 padded in normal format. | |
verbose | Forward the message after replacing the original Option 82 with the Option 82 padded in verbose format. | ||
user-defined | Forward the message after replacing the original Option 82 with the user-defined Option 82. | ||
no Option 82 | N/A | normal | Forward the message after adding the Option 82 padded in normal format. |
N/A | verbose | Forward the message after adding the Option 82 padded in verbose format. | |
N/A | user-defined | Forward the message after adding the user-defined Option 82. |