3Com 5500-SI Switch User Manual


 
130 CHAPTER 10: DHCP SERVER CONFIGURATION
The static-bind ip-address command and the static-bind mac-address command can
be executed repeatedly. In this case, the new configuration overwrites the previous
one.
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.
The network command can be executed repeatedly. In this case, the new
configuration overwrites the previous one.
The dhcp server forbidden-ip command can be executed repeatedly. That is, you can
repeatedly configure IP addresses that are not dynamically assigned to DHCP clients.
Configuring DNS
Services for DHCP
Clients
If a host accesses the Internet through domain names, DNS (domain name system) is
needed to translate the domain names into the corresponding IP addresses. To enable
DHCP clients to access the Internet through domain names, a DHCP server is required
to provide DNS server addresses while assigning IP addresses to DHCP clients.
Currently, you can configure up to eight DNS server addresses for a DHCP address
pool.
Table 114 Configure to assign IP addresses dynamically
Operation Command Description
Enter system view system-view -
Create a DHCP address
pool and enter DHCP
address pool view
dhcp server
ip-pool pool-name
Required
By default, no DHCP address pool is created.
Set the IP address
segment whose IP address
are to be assigned
dynamically
network ip-address
[ mask-length |
mask mask ]
Required
By default, no IP address segment is set. That is,
no IP address is available for being assigned.
Configure the lease time expired { day day [
hour hour [ minute
minute ] ] |
unlimited }
Optional
The default lease time is one day.
Return to system view Quit -
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.