Operation Manual – DHCPH3C S5600 Series Ethernet Switches Chapter 2 DHCP Server Configuration2-322.7 Configuring DHCP Accounting Functions2.7.1 Introduction to DHCP AccountingDHCP accounting allows a DHCP server to notify the RADIUS server of the start/end ofaccounting when it assigns/releases a lease. The cooperation of DHCP server andRADIUS server implements the network accounting function and ensures networksecurity at the same time.2.7.2 DHCP Accounting FundamentalsAfter you complete AAA and RADIUS configuration on a switch with the DHCP serverfunction enabled, the DHCP server acts as a RADIUS client. For the authenticationprocess of the DHCP server acting as a RADIUS client, refer to AAA Operation in thismanual. The following describes only the accounting interaction between DHCP serverand RADIUS server.z After sending a DHCP-ACK packet with the IP configuration parameters to theDHCP client, the DHCP server sends an Accounting START packet to a specifiedRADIUS server. The RADIUS server processes the packet, makes a record, andsends a response to the DHCP server.z Once releasing a lease, the DHCP server sends an Accounting STOP packet tothe RADIUS server. The RADIUS server processes the packet, stops therecording for the DHCP client, and sends a response to the DHCP server. A leasecan be released for the reasons such as lease expiration, a release requestreceived from the DHCP client, a manual release operation, an address poolremoval operation.Note:If the RADIUS server of the specified domain is unreachable, the DHCP server sendsup to three Accounting START packets (including the first sending attempt) at regularintervals. If the three packets bring no response from the RADIUS server, the DHCPserver does not send Accounting START packets any more.2.7.3 DHCP Accounting ConfigurationI. PrerequisitesBefore configuring DHCP accounting, make sure that:z The DHCP server is configured and operates properly. Address pools and leasetime are configured.z DHCP clients are configured and DHCP service is enabled.
