H3C S3600 Series Operation Manual

Also see for H3C S3600 Series: Datasheet Installation manual Command manual Operation manual Command manual

Contents

H3C S3600 Series Operation Manual Manual pdf 28 page image

Operation Manual – DHCPH3C S3600 Series Ethernet Switches-Release 1510 Chapter 2 DHCP Server Configuration2-212.4 DHCP Security ConfigurationDHCP security configuration is needed to ensure the security of DHCP service.2.4.1 PrerequisitesBefore configuring DHCP security, you should first complete the DHCP serverconfiguration (either global address pool-based or interface address pool-based DHCPserver configuration).2.4.2 Configuring Private DHCP Server DetectingA private DHCP server on a network also answers IP address request packets andassigns IP addresses to DHCP clients. However, the IP addresses they assigned mayconflict with those of other hosts. As a result, users cannot normally access networks.This kind of DHCP servers are known as private DHCP servers.With the private DHCP server detecting function enabled, when a DHCP client sendsthe DHCP-REQUEST packet, the DHCP server tracks the information (such as the IPaddress and interface) of the DHCP server which assigns the IP address to the client toenable the administrator to detect private DHCP servers in time and take propermeasures.Table 2-20 Enable detection of a private DHCP serverOperation Command DescriptionEnter system view system-view —Enable the privateDHCP serverdetecting functiondhcp server detectRequiredBy default, the private DHCPserver detecting function isdisabled.2.4.3 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 IP addressbefore 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 ping 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 the pingoperations reaches the specified maximum number. The DHCP server assigns the IP