HP-UX IP Address and Client Management Administrator's Guide HP-UX 11i v2, HP-UX 11i v3

In this example, the presence of the ba tag indicates that the broadcast flag is turned on. Many
clients need this flag, therefore it exists in most pool group entries. The pool-name is a label
that helps the system administrator identify the pool group. The client is not aware of this name.
The beginning and end of the address range in the pool is defined by
addr-pool-start-address and addr-pool-last-address. The pool group in this
example contains 10 addresses on the 15.13.100 subnet: 15.13.100.20 through 15.13.100.29.
NOTE: A subnet must contain only one pool group that forms the default IP address group.
Figure 4-2 Devices Configured in a DHCP Group
In Figure 4-2, assume that a particular group is configured and the clients Client1, Client2, and
Client3 belong to this group. Each device in this group has the same group name and an IP
address that is within the group’s IP address range. The IP addresses within the group’s range
collectively form a pool of addresses. When Client1, Client2, or Client3 perform a boot request,
they are automatically assigned an IP address, which is not in use, from this pool of addresses.
DHCP allows you to exclude certain addresses within a group if you do not want them used.
You can also define many values for the devices of a group including address lease times, DNS
servers, NIS servers, and many other optional parameters. See the example “Complex DHCP
Pool and Device Group Files ” (page 122) for more information.
DHCP supports the subnet selection option. This option contains a single IPv4 address that
specifies the address of a subnet. If this option exists in the DHCP client request, the DHCP server
must allocate the address on either the subnet specified in the subnet selection option or a subnet
on the same network segment as the subnet that is specified in the subnet selection option.
For more information on the subnet selection option, see RFC 3011 (The IPv4 Subnet Selection
Option for DHCP).
DHCP Device Group
You can create a device group by configuring similar client devices and specifying a unique IP
address range for the group of client devices. The device group is similar to a pool group, except
that in a device group all the clients must be of the same type. For example, all the clients must
be printers or X terminals. These clients must match the device type specified in the class-id
field in the /etc/dhcptab file. In the following example, all the clients in this device group
must be X terminals.
DHCP_DEVICE_GROUP:\
class-name=XTERM_GROUP:\
class-id=”Xterminal:”\ subnet-mask=255.255.255.0:\ addr-pool-start-address=
15.13.100.50\ addr-pool-last-address= 15.13.100.59:
Configuring DHCP to Assign and Distribute IP Addresses 121