PLANET WGSW-52040 - Manual (Page 281)

33.4 DHCP Option 82 Troubleshooting
 DHCP option 82 is implemented as a sub-function module of DHCP Relay Agent.
Before using it, users should make sure that the DHCP Relay Agent is configured
correctly.
 DHCP option 82 needs the DHCP Relay Agent and the DHCP server cooperate to
finish the task of allocating IP addresses. The DHCP server should set allocating
policy correctly depending on the network topology of the DHCP Relay Agent, or,
even the Relay Agent can operate normally, the allocation of addresses will fail.
When there is more than one kind of Relay Agent, please pay attention to the
retransmitting policy of the interface DHCP request messages.
 To implement the option 82 function of DHCP Relay Agent, the “debug dhcp relay
packet” command can be used during the operating procedure, including adding the
contents of option 82, the retransmitting policy adopted, the option 82 contents of the
server peeled by the Relay Agent and etc., such information can help users to do
troubleshooting.
 To implement the option 82 function of DHCP server, the “debug ip dhcp server
packet” command can be used during the operating procedure to display the
procedure of data packets processing of the server, including displaying the
identified option 82 information of the request message and the option 82
information returned by the reply message.
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