Operation Manual – DHCPH3C S7500 Series Ethernet Switches Chapter 2 DHCP Server Configuration2-17To do… Use the command… RemarksEnter system view system-view —Enable the private DHCPserver detecting function dhcp server detectRequiredBy default, the privateDHCP server detectingfunction is disabled2.4.3 Configuring IP Address DetectingTo avoid IP address conflicts caused by assigning the same IP address to multipleDHCP clients simultaneously, you can configure a DHCP server to detect an IPaddress before it assigns the address to a DHCP client.IP address detecting is achieved by performing ping operations. To detect whether anIP address is currently in use, the DHCP server sends an ICMP packet with the IPaddress to be assigned as the destination and waits for a response. If the DHCPserver receives no response within a specified time, it resends an ICMP packet. Thisprocedure repeats until the DHCP server receives a response or the number of thesent ICMP packets reaches the specified maximum number. The DHCP serverassigns the IP address to the DHCP client only when no response is received duringthe whole course, thus ensuring that an IP address is assigned to one DHCP clientexclusively.Follow these steps to configure IP address detecting:To do… Use the command… RemarksEnter system view system-view —Set the maximum numberof ICMP packets a DHCPserver sends in a ping testdhcp server pingpackets numberOptionalBy default, a DHCP serverperforms the ping operationtwice to test an IP addressSet the response timeouttime of each ICMP packetdhcp server pingtimeout millisecondsOptionalThe default timeout time is500 milliseconds
