Administrator Guide

17 : BIOS vs. UEFI | Doc ID 20444677 | June 2018
4.4.2 HTTP Boot Server Configuration
The HTTP boot server is composed of two major parts: DHCP server and HTTP server. A domain name
system (DNS) server is necessary as well if the URI specifies the domain name instead of the IP address.
The bootstrap program provided by the HTTP boot server must be a UEFI bootable image (PE/COFF format).
For Linux environments, UEFI-capable bootstrap programs include ELILO, grub2, and syslinux. Windows
environments (Windows Server 2012 and later) use bootmgfw.efi.
4.5 UEFI iSCSI Boot Configuration
UEFI iSCSI Boot enables booting a system to a boot image located on a network-attached system. The
network-attached system with the boot image is known as the “target.” The other system, the “initiator,” uses
block transactions (similar to the way a hard-disk controller accesses a local hard-disk drive) to access the
bootable software stored on the network-attached target.
Minimal changes are required for the iSCSI initiator and iSCSI target when transitioning from BIOS boot mode
to UEFI boot mode. The following sections describe these changes.
4.5.1 UEFI iSCSI Initiator Configuration
As with other system settings, the UEFI iSCSI configuration settings are accessible through integrated Dell
Remote Access Controller (iDRAC) interfaces such as RACADM, or locally through the System Setup utility.
In BIOS boot mode, individual network devices provide the iSCSI settings in System Setup > Device Settings.
However, in UEFI boot mode, iSCSI settings are configured in the BIOS pages (System Setup > System
BIOS > Network Settings > UEFI iSCSI Settings). See Figure 7. The initiator name is configured on this page;
this is the unique name (in IQN format) for the iSCSI initiator. The “Network Settings” option in the System
BIOS page is available only in UEFI boot mode.
There are two iSCSI logical devices that can be configured for iSCSI boot. Each logical device appears as a
separate entry in the UEFI boot order. When an iSCSI logical device is enabled, its settings are available in its
iSCSI Device Settings menu. Figures 8 and 9 show the contents of the iSCSI Device Settings menu.