Ignite-UX Administration Guide for HP-UX 11i (B3921-90080, November 2013)

Configuring an Ignite Server to Boot Anonymous Itanium-Based Clients
Working With DHCP
Even on a simple network, there could be devices such as printers requesting network boot. This
section describes the challenges involved and solutions for DHCP booting and then acquiring IP
addresses for networking.
NOTE: If you are using your Ignite-UX server for DHCP booting, you can set DHCP boot IP
addresses from the Ignite-UX GUI by selecting Options→Server Configuration as described in
“Configuring Server Options” (page 37).
Understanding PXE Booting of Itanium-Based Systems
When an Itanium-based system boots over the network, it sends out a PXE boot request. The PXE
protocol is built on top of DHCP. This can cause confusion if there is more than one DHCP server
configured to respond to PXE boot requests.
It is not possible for an Itanium-based system to specify the server from which to accept DHCP boot
services, ignoring boot offers from all other servers. In other words, there is not an Itanium-based
equivalent for the PA-RISC boot command, boot lan.192.10.10.10 install, which causes
the system to ignore any response except from the IP address 192.10.10.10. This functionality is
known as server selection.
It is possible for many Itanium-based systems to perform directed boot, where server and client
networking information is stored in client firmware and DHCP is not used. For more information
on directed boot, see “Direct Boot Profiles for Itanium-Based Systems” (page 103).
When an Itanium-based system sends out a PXE boot request, it tries to boot from the first PXE
response it gets. If no PXE responses are received within a certain time, the system uses the first
DHCP response it gets. If any of these responses are inadequate for network booting, the PXE boot
attempt fails and an error message is displayed on the console of the requesting system. The
information displayed with PXE errors is usually not explicit enough to determine the cause of the
problem (see “Common Network Booting Errors” (page 231)).
For any network where there will be PXE boot requests from Itanium-based systems, only DHCP
servers that can supply enough information for a successful boot should be configured to respond.
If you have a DHCP server that responds to every DHCP request, regardless of whether it is a PXE
request or not, it almost definitely interferes with PXE boot requests from Itanium-based servers. The
boot request fails when a normal DHCP response is received in response to a PXE boot request.
In addition to boot failure, the inability to select a boot server can lead to installation of the wrong
operating system. Having PXE servers that respond with different boot content on the same network
can cause confusion. For example, if there is a system supporting Linux boot and a system supporting
HP-UX boot on the same network, they can each send a response to a PXE boot request, and the
first server to respond will be used. It is not predictable which server would be used for boot.
Interference with a PXE request from a DHCP server is a configuration issue on the DHCP server
side. This issue is not specific to HP-UX or Ignite-UX, but rather is related to the way firmware
performs a PXE boot.
IMPORTANT: When you configure DHCP servers, make sure there is only one DHCP server on
the network that is configured to respond to Itanium-based system PXE boot requests, and that the
server is running HP-UX if you want to install HP-UX.
Ignite-UX Server and Boot Helper Setup for DHCP
HP-UX 11i v3 and 11i v2 supports dhcp_device_group options that improve anonymous client
DHCP booting for Itanium-based clients. The two configuration keywords re and ncid are used
in a DHCP device pool group for this purpose.
44 Simple Network: Creating a Server for Anonymous Clients