Novell ZENWORKS 10 CONFIGURATION MANAGEMENT SP3 - PREBOOT SERVICES AND IMAGING REFERENCE 10.3 16-04-2010 User Manual page 63

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.
LAN Configuration Differences Between the Same and Separate Servers
Table 2-3
Information On the Same Server
Configuration Because Preboot Services and DHCP are
running on the same server, option tag 60
must be set on the DHCP server.
For information on setting this tag, see
"Configuring LAN Environments for
Preboot Services" on page
Advantages Easy installation and setup.
No network configuration is required.
Disadvantages DHCP server configuration is
required (option tag 60).
Limited use, because a single-LAN
environment only exists in small lab-
type networks.
The following illustrates the differences for a WAN/VLAN configuration between installing Preboot
Services on the same server as DHCP, or on a separate server. In this case, all PXE devices over the
entire WAN/VLAN connect to the Preboot Services Imaging Server.
On Separate Servers
None required.
64.
Easiest installation and setup.
No network configuration is required.
No DHCP server configuration is
required.
Limited use, because a single-LAN
environment only exists in small lab-
type networks.
Setting Up Preboot Services and Imaging 63