You need a PXELINUX configuration file to boot the ESXi installer on a legacy BIOS system. The configuration file defines the menu displayed to the target ESXi host as it starts.

This section gives general information about PXELINUX configuration files.

For syntax details, see the SYSLINUX website at

Required Files

In the PXE configuration file, you must include paths to the following files:

  • mboot.c32 is the boot loader.
  • boot.cfg is the boot loader configuration file.

See About the boot.cfg File

Filename for the PXE Configuration File

For the filename of the PXE configuration file, select one of the following options:

  • 01-mac_address_of_target_ESXi_host. For example, 01-23-45-67-89-0a-bc
  • The target ESXi host IP address in a hexadecimal notation.
  • default
The initial boot file pxelinux.0 tries to load a PXE configuration file in the following order:
  1. It tries with the MAC address of the target ESXi host, prefixed with its ARP type code, which is 01 for Ethernet.
  2. If that attempt fails, it tries with the hexadecimal notation of target ESXi system IP address.
  3. Ultimately, it tries to load a file named default.

File Location for the PXE Configuration File

Save the file in /tftpboot/pxelinux.cfg/ on the TFTP server.

For example, you might save the file on the TFTP server at /tftpboot/pxelinux.cfg/01-00-21-5a-ce-40-f6. The MAC address of the network adapter on the target ESXi host is 00-21-5a-ce-40-f6.