Novell ZENWORKS LINUX MANAGEMENT 7.3 IR2 - ADMINISTRATION GUIDE 02-12-2010 Administration Manual page 368

Network Configuration
The configuration required to run Preboot Services in your network depends on your network setup.
Design your network so that PXE devices can effectively connect to the server where the Preboot
Services daemons are running. Make sure you consider the number of PXE devices to be installed
on the network and the bandwidth available to service these devices. To understand how the devices
and servers need to interact during the Preboot Services process, see
Services Processes," on page
You can configure Preboot Services where Preboot Services and DHCP are running on the same
server or on different servers in both LAN and WAN/VLAN environments:
"Understanding Preboot Services in LAN and WAN/VLAN Environments" on page 368
"Comparing Preboot Services Setups in LAN and WAN/VLAN Environments" on page 368
"Configuring LAN Environments for Preboot Services" on page 370
"Configuring a WAN/VLAN with Preboot Services and DHCP Running on the Same Server"
on page 370
"Configuring a WAN/VLAN With Preboot Services and DHCP Running on Separate Servers"
on page 371
Understanding Preboot Services in LAN and WAN/VLAN Environments
Imaging servers should be installed so that PXE devices have access to imaging services within their
LAN. A good design ensures that a client does not need to connect to imaging services through a
slow WAN link.
Although you can have any number of imaging servers, generally only one Proxy DHCP server
should be enabled per DHCP server scope.
In a WAN, the PXE device is usually separated from the Proxy DHCP and DHCP servers by one or
more routers. The PXE device broadcasts for DHCP information, but by default the router does not
forward the broadcast to the servers, causing the Preboot Services session to fail.
In a VLAN (Virtual LAN) environment, the PXE device is logically separated from the Proxy
DHCP server and the DHCP server by a switch. At the IP level, this configuration looks very similar
to a traditional WAN (routed) environment.
In a typical VLAN environment, the network is divided into a number of subnets by configuring
virtual LANs on the switch. Devices in each virtual LAN usually obtain their IP address information
from a central DHCP server. In order for this system to work, it is necessary to have Bootp or IP
helpers configured on each gateway. These helpers forward DHCP requests from devices in each
subnet to the DHCP server, allowing the DHCP server to respond to devices in that subnet.
Comparing Preboot Services Setups in LAN and WAN/VLAN Environments
The following illustrates the differences for a LAN configuration between installing Preboot
Services on the same server as DHCP, or on a separate server. In this case, only the PXE devices on
the LAN connect to the Preboot Services imaging server.
368 Novell ZENworks 7.3 Linux Management Administration Guide
339.
Section 28.4, "The Preboot