Installing HP-UX 11.0 and Updating HP-UX 10.x to 11.0 HP 9000 Computers Edition 1

206 Appendix A

Conﬁguring for a DHCP Server

Using DHCP Services: Overview

DHCP provides the following features:

• Allows for dynamically allocating IP addresses and hostnames.

• Automatically supplies most of the networking defaults that are

requested during a system installation or ﬁrst time boot.

• Provides for on-going IP address maintenance via a concept of an "IP

address lease". Having a lease on an IP address means that if the

system "goes away" for a speciﬁed period of time without renewing

the lease, then that IP address can be given to a different system that

request a new IP address lease.

• Assists in reestablishing valid network parameters when a system

has been moved from one DHCP-managed network to another.

The environment where DHCP works best is where the following

conditions and restrictions exist:

• When a range of currently unused IP addresses can be allocated for

use during new system bring-up.

• When the IP address-to-hostname mapping can be made ahead of

time (before the system to use it is installed). And this mapping can

be conﬁgured in the name services database before installing a

system.

• When the IP address and hostname that get assigned to a system are

not important. A system will keep the same IP address and hostname

for as long as it renews the lease. However the original assignment is

arbitrary.

• When the person installing the systems does not desire to choose a

hostname for the system, but rather accepts the one already

registered for the IP address supplied by DHCP. This will ensure that

the system will be recognized immediately by its hostname.

• When existing systems that did not use DHCP before will continue

not to use it. Or, if they did, they would be willing to accept an

arbitrary hostname and IP address. This is the same as with a new

system. There currently is no tool available for pre-loading the DHCP

database with existing IP addresses and identifying the systems they

belong to. A tool to do this may be available in a future release.