6.5.1

PXE Boot Background Information
Understanding the PXE boot process can help you during troubleshooting.
TFTP Server
Trivial File Transfer Protocol (TFTP) is similar to the FTP service, and is typically used only for network
booting systems or loading firmware on network devices such as routers. TFTP is available on Linux and
Windows.
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Most Linux distributions include a copy of the tftp-hpa server. If you require a supported solution,
purchase a supported TFTP server from your vendor of choice. You can also acquire a TFTP server
from one of the packaged appliances on the VMware Marketplace.
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If your TFTP server will run on a Microsoft Windows host, use tftpd32 version 2.11 or later. See
http://tftpd32.jounin.net/.
SYSLINUX, PXELINUX, and gPXELINUX
If you are using PXE in a legacy BIOS environment, you need to understand the different boot
environments.
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SYSLINUX is an open source boot environment for machines that run legacy BIOS firmware. The
ESXi boot loader for BIOS systems, mbootc.32, runs as a SYSLINUX plugin. You can configure
SYSLINUX to boot from several types of media, including disk, ISO image, and network. You can find
the SYSLINUX package at http://www.kernel.org/pub/linux/utils/boot/syslinux/.
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PXELINUX is a SYSXLINUX configuration for booting from a TFTP server according to the PXE
standard. If you use PXELINUX to boot the ESXi installer, the pxelinux.0 binary file, mboot.c32,
the configuration file, the kernel, and other files are all transferred by TFTP.
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gPXELINUX is a hybrid configuration that includes both PXELINUX and gPXE and supports booting
from a Web server. gPXELINUX is part of the SYSLINUX package. If you use gPXELINUX to boot the
ESXi installer, only the gpxelinux.0 binary file, mboot.c32, and the configuration file are transferred
via TFTP. The remaining files are transferred via HTTP. HTTP is typically faster and more reliable
than TFTP, especially for transferring large amounts of data on a heavily loaded network.
Note VMware currently builds the mboot.c32 plugin to work with SYSLINUX version 3.86 and tests PXE
booting only with that version. Other versions are likely to be incompatible. This is not a statement of
limited support. For support of third-party agents that you use to set up your PXE booting infrastructure,
contact the vendor.
UEFI PXE and iPXE
Most UEFI firmware natively includes PXE support that allows booting from a TFTP server. The firmware
can directly load the ESXi boot loader for UEFI systems, mboot.efi. Additional software such as
PXELINUX is not required.
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