H3C Technologies H3C S3600 Series Switches - Manual (Page 676)

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Follow these steps to enable DHCP:
To do… Use the command… Remarks
Enter system view system-view —
Enable DHCP dhcp enable
Required
Enabled by default.
Note that: Among S3600 series switches, only S3600-EI switches support this command. DHCP is
always enabled on S3600-SI series switches.
Correlating a DHCP Server Group with a Relay Agent Interface
To enhance reliability, you can set multiple DHCP servers on the same network. These DHCP servers
form a DHCP server group. When an interface of the relay agent establishes a correlation with the
DHCP server group, the interface will forward received 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… Remarks
Enter system view system-view —
Configure the DHCP server IP
address(es) in a specified
DHCP server group
dhcp-server groupNo ip
ip-address&<1-8>
Required
By default, no DHCP server IP
address is configured in a
DHCP server group.
interface interface-type
interface-number
Map an interface to a DHCP
server group
dhcp-server groupNo
Required
By default, a VLAN interface is
not mapped to any DHCP
server group.
To improve security and avoid malicious attack to the unused SOCKETs, S3600 Ethernet 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-server command, the
DHCP relay agent is enabled. At the same time, UDP 67 and UDP 68 ports used by DHCP are
enabled.
z When the mapping between a VLAN interface and a DHCP server group is removed with the undo
dhcp-server command, DHCP services are disabled. At the same time, UDP 67 and UDP 68 ports
are disabled.