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PXEBOOT(8) System Manager's Manual (i386) PXEBOOT(8)

pxebooti386-specific second-stage PXE bootstrap

pxeboot is a modified version of the i386 second-stage bootstrap program, boot(8), configured to run under Intel's Preboot Execution Environment (PXE). PXE is a form of smart boot ROM, built into many Ethernet cards from Intel, 3Com, and other manufacturers.

The computer's PXE boot ROM contacts a DHCP server by broadcasting a request on the network. It gets an IP address from the DHCP server, then it is told the name of the boot program to download — in this case, the boot program is pxeboot. The ROM downloads the boot program using TFTP, then executes it.

The pxeboot boot program will look for an /etc/boot.conf configuration file on the TFTP server. If it finds one, it processes the commands within it. boot.conf processing can be skipped by holding down either Control key as pxeboot starts.

pxeboot then sits in a loop, processing commands given by the user. It accepts all the commands accepted by boot(8).

If no commands are given for a short time, pxeboot will then attempt to load the OpenBSD kernel bsd via TFTP. It may be told to boot an alternative kernel, either by commands in the boot.conf file, or by commands typed by the user at the boot> prompt. pxeboot can be used for diskless(8) setups or to load the bsd.rd install kernel for network installs.

To prepare a server to support network booting, the dhcpd(8) and tftpd(8) services should be enabled and configured.

pxeboot and the kernel should be copied into the TFTP server's root directory (typically /tftpboot). A boot.conf file may be created if required (e.g. /tftpboot/etc/boot.conf).

A sample configuration file for dhcpd(8) might be as follows:

option domain-name "";
option routers;
option subnet-mask;
option broadcast-address;
option domain-name-servers;
server-name "DHCPserver";

default-lease-time 120;
max-lease-time 120;

subnet netmask {
    filename "pxeboot";

See dhcpd(8) and dhcpd.conf(5) for more information.

PXE-specific second-stage bootstrap
pxeboot configuration file (read from TFTP server)
DHCPD configuration file
Default root directory for tftpd(8)

Boot the install kernel:

boot> bsd.rd

The same thing:

boot> boot tftp:bsd.rd

dhcpd.conf(5), boot(8), boot_i386(8), dhcpd(8), diskless(8), tftpd(8)

Intel Corporation, Preboot Execution Environment (PXE) Specification, Version 2.1, September 20, 1999.

The pxeboot command first appeared in OpenBSD 3.5.

May 20, 2014 OpenBSD-6.8