HP UX System Management Software manual Configuring Dhcp services, Overview of Dhcp services

B Configuring DHCP services

HP-UX and Ignite-UX support retrieving network information using the Dynamic Host Configuration Protocol (DHCP). This appendix describes setting up DHCP.

Ignite-UX allows for setting up DHCP for use during system installation. This appendix is for those who want to use DHCP for ongoing IP address management, as well as for system installation.

All partitionable Itanium-based systems provide an alternative to using DHCP for network booting. This EFI functionality is also found in other, non-partitionable systems. With these profiles, you can supply all the networking information needed to contact an Ignite-UX server and perform an install or recovery. For more information see “Direct boot profiles for Itanium-based systems” (page 102).

Overview of DHCP services

DHCP provides these features:

•Enables dynamic allocation of IP addresses and hostnames.

•Automatically supplies most of the networking defaults that are requested during a system installation or first-time boot.

•Provides for ongoing IP address maintenance using 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 requests a new IP address lease.

•Assists in reestablishing valid network parameters when a system has been moved from one DHCP-managed network to another.

DHCP works best under these conditions and restrictions:

•When a range of currently unused IP addresses can be allocated for use during new system installation.

•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 you do not want to choose a hostname for the system and will accept the hostname already registered for the IP address supplied by DHCP. This ensures that the system will be recognized immediately by its hostname.

•When existing systems that did not use DHCP before are willing to accept an arbitrary hostname and IP address.

An alternative to using DHCP is to create /etc/bootptab entries for each specific client on the network. This allows for specific IP address mappings and greater control. For more detail, see “Using bootptab as an alternative to DHCP ” (page 238).

For additional information regarding the use of DHCP with Itanium-based systems, see “Configuring an Ignite server to boot anonymous Itanium-based clients” (page 44) and see the HP-UX IP Address and Client Management Administrator's Guide.

236 Configuring DHCP services