3Com Switch 7750 Configuration Guide Guide

568 CHAPTER 54: DHCP SERVER CONFIGURATION
■ The IP addresses statically bound in interface address pools and the interface IP
addresses must be in the same segment.
■ There is no limit to the number of IP addresses statically bound in an interface
address pool, but the IP addresses statically bound in interface address pools
and the interface IP addresses must be in the same segment.
■ An IP address can be statically bound to only one MAC address. A MAC
address can be bound with only one IP address statically.
■ The IP address to be statically bound cannot be an interface IP address of the
DHCP server; otherwise the static binding does not take effect.
Configuring to assign IP addresses dynamically
As an interface-based address pool is created after the interface is assigned a valid
unicast IP address, the IP addresses contained in the address pool belong to the
network segment where the interface resides in and are available to the interface
only. So specifying the range of the IP addresses to be dynamically assigned is
unnecessary.
To avoid IP address conflicts, the IP addresses to be dynamically assigned to DHCP
clients are those 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.
Tabl e 442 Configure to assign IP addresses dynamically
Operation Command Description
Enter system view system-view -
Configure the lease
time
Configure for the
current interface
interface
interface-type
interface-number
Optional
The default lease time
is one day
dhcp server expired
{ day day [ hour hour
[ minute minute ] ] |
unlimited }
quit
Configure multiple
interfaces in system
view
dhcp server expired
{ day day [ hour hour
[ minute minute ] ] |
unlimited } {
interface
interface-type
interface-number [ to
interface-type
interface-number ] |
all }
Specify the IP addresses that are not
dynamically assigned
dhcp server
forbidden-ip
low-ip-address [
high-ip-address ]
Optional
By default, all IP
addresses in a DHCP
address pool are
available for being
dynamically assigned.