Operation Manual – DHCPH3C S5600 Series Ethernet Switches Chapter 3 DHCP Relay Agent Configuration3-5To do… Use the command… RemarksEnter system view system-view —Enable DHCP dhcp enable RequiredEnabled by default.3.2.3 Correlating a DHCP Server Group with a Relay Agent InterfaceTo enhance reliability, you can set multiple DHCP servers on the same network. TheseDHCP servers form a DHCP server group. When an interface of the relay agentestablishes a correlation with the DHCP server group, the interface will forwardreceived DHCP packets to all servers in the server group.Follow these steps to correlate a DHCP server group with a relay agent interface:To do… Use the command… RemarksEnter system view system-view —Configure the DHCPserver IP address(es) in aspecified DHCP servergroupdhcp-server groupNo ipip-address&<1-8>RequiredBy default, no DHCPserver IP address isconfigured in a DHCPserver group.interface interface-typeinterface-numberMap an interface to aDHCP server groupdhcp-server groupNoRequiredBy default, a VLANinterface is not mapped toany DHCP server group.Note:To improve security and avoid malicious attack to the unused SOCKETs, S5600Ethernet switches provide the following functions:z UDP 67 and UDP 68 ports used by DHCP are enabled only when DHCP is enabled.z UDP 67 and UDP 68 ports are disabled when DHCP is disabled.The corresponding implementation is as follows:z When a VLAN interface is mapped to a DHCP server group with the dhcp-servercommand, the DHCP relay agent is enabled. At the same time, UDP 67 and UDP 68ports used by DHCP are enabled.z When the mapping between a VLAN interface and a DHCP server group is removedwith the undo dhcp-server command, DHCP services are disabled. At the sametime, UDP 67 and UDP 68 ports are disabled.
