3com 5500-ei pwr Installation Instruction

 

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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: 

Enter 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. 

 

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. 

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.