H3C S3600 Series Operation Manual page 15

Operation Manual – DHCP
H3C S3600 Series Ethernet Switches-Release 1510
Note:
To improve security and avoid malicious attack to the unused SOCKETs, S3600
Ethernet switches provide the following functions:
UDP 67 and UDP 68 ports used by DHCP are enabled only when DHCP is enabled.
UDP 67 and UDP 68 ports are disabled when DHCP is disabled.
The corresponding implementation is as follows:
After a DHCP address pool is created by executing the dhcp server ip-pool
command, the UDP 67 and UDP 68 ports used by DHCP are enabled.
After a DHCP address pool is deleted by executing the undo dhcp server ip-pool
command and all other DHCP functions are disabled, UDP 67 and UDP 68 ports
used by DHCP are disabled accordingly.
II. Configuring to assign IP addresses dynamically
IP addresses dynamically assigned to DHCP clients (including those that are
permanently leased and those that are temporarily leased) belong to addresses
segments that are previously specified. Currently, an address pool can contain only one
address segment, whose ranges are determined by the subnet mask.
To avoid IP address conflicts, the IP addresses to be dynamically assigned to DHCP
clients are those that are not occupied by specific network devices (such as gateways
and FTP servers).
The lease time can differ with address pools. But that of the IP addresses of the same
address pool are the same. Lease time is not inherited, that is to say, the lease time of
a child address pool is not affected by the configuration of the parent address pool.
Table 2-5 Configure to assign IP addresses dynamically
Operation
Enter system view
Create a DHCP
address pool and
enter
address pool view
Set the IP address
segment whose IP
address are to be
assigned
dynamically
Configure
lease time
Command
system-view
dhcp server
DHCP
pool-name
network ip-address [ mask
mask ]
expired { day day [ hour
the
hour [ minute minute ] ] |
unlimited }
2-8
Chapter 2 DHCP Server Configuration
Description
—
Required
ip-pool
By default, no global DHCP
address pool is created
Required
By default, no IP address
segment is set. That is, no IP
address is available for being
assigned
Optional
The default lease time is one
day