H3C Technologies H3C S3600 Series Switches - Manual (Page 664)

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will assign the IP address to the requesting client (The DHCP client probes the IP address by sending
gratuitous ARP packets).
Follow these steps to configure IP address detecting:
To do… Use the command… Remarks
Enter system view system-view —
Specify the number of ping
packets dhcp server ping packets
number
Optional
Two ping packets by default.
Configure a timeout waiting for
ping responses dhcp server ping timeout
milliseconds
Optional
500 ms by default.
Configuring DHCP Accounting Functions
Introduction to DHCP Accounting
DHCP accounting allows a DHCP server to notify the RADIUS server of the start/end of accounting
when it assigns/releases a lease. The cooperation of DHCP server and RADIUS server implements the
network accounting function and ensures network security at the same time.
DHCP Accounting Fundamentals
After you complete AAA and RADIUS configuration on a switch with the DHCP server function enabled,
the DHCP server acts as a RADIUS client. For the authentication process of the DHCP server acting as
a RADIUS client, refer to AAA Operation in this manual. The following describes only the accounting
interaction between DHCP server and RADIUS server.
z After sending a DHCP-ACK packet with the IP configuration parameters to the DHCP client, the
DHCP server sends an Accounting START packet to a specified RADIUS server. The RADIUS
server processes the packet, makes a record, and sends a response to the DHCP server.
z Once releasing a lease, the DHCP server sends an Accounting STOP packet to the RADIUS
server. The RADIUS server processes the packet, stops the recording for the DHCP client, and
sends a response to the DHCP server. A lease can be released for the reasons such as lease
expiration, a release request received from the DHCP client, a manual release operation, an
address pool removal operation.
If the RADIUS server of the specified domain is unreachable, the DHCP server sends up to three
Accounting START packets (including the first sending attempt) at regular intervals. If the three packets
bring no response from the RADIUS server, the DHCP server does not send Accounting START
packets any more.