H3C Technologies H3C S12500-X Series Switches - Manual (Page 63)

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Figure 21 DHCP relay agent operation
DHCP relay agent support for Option 82
Option 82 records the location information about the DHCP client. It enables the administrator to locate
the DHCP client for security and accounting purposes, and to assign IP addresses in a specific range to
clients. For more information, see " Relay agent option (Option 82) ."
If the DHCP relay agent supports Option 82, it handles DHCP requests by following the strategies
described in Table 3 .
If a response returned by the DHCP server contains Option 82, the DHCP relay agent removes the Option
82 before forwarding the response to the client.
Table 3 Handling strategies of the DHCP relay agent
If a DHCP request
has…
Handling
strategy
The DHCP relay agent…
Option 82
Drop Drops the message.
Keep Forwards the message without changing Option 82.
Replace
Forwards the message after replacing the original Option 82 with the
Option 82 padded according to the configured padding format,
padding content, and code type.
No Option 82 N/A
Forwards the message after adding Option 82 padded according to
the configured padding format, padding content, and code type.
DHCP relay agent configuration task list
Tasks at a glance
(Required.) Enabling DHCP
(Required.) Enabling the DHCP relay agent on an interface
(Required.) Specifying DHCP servers on a relay agent
(Optional.) Configuring the DHCP relay agent security functions