1.\" Copyright (c) 1999 Doug White 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.Dd February 15, 2021 26.Dt PXEBOOT 8 27.Os 28.Sh NAME 29.Nm pxeboot 30.Nd Preboot Execution Environment (PXE) bootloader 31.Sh DESCRIPTION 32The 33.Nm 34bootloader is a modified version of the system third-stage bootstrap 35.Xr loader 8 36configured to run under Intel's Preboot Execution Environment (PXE) system. 37PXE is a form of smart boot ROM, built into Intel EtherExpress Pro/100 and 383Com 3c905c Ethernet cards, and Ethernet-equipped Intel motherboards. 39PXE supports DHCP configuration and provides low-level NIC access services. 40.Pp 41The DHCP client will set a DHCP user class named 42.Va FreeBSD 43to allow flexible configuration of the DHCP server. 44.Pp 45The 46.Nm 47bootloader retrieves the kernel, modules, 48and other files either via NFS over UDP or by TFTP, 49selectable through compile-time options. 50In combination with a memory file system image or NFS-mounted root file system, 51.Nm 52allows for easy, 53EEPROM-burner free construction of diskless machines. 54.Pp 55The 56.Nm 57binary is loaded just like any other boot file, 58by specifying it in the DHCP server's configuration file. 59Below is a sample configuration for the ISC DHCP v3 server: 60.Bd -literal -offset indent 61option domain-name "example.com"; 62option routers 10.0.0.1; 63option subnet-mask 255.255.255.0; 64option broadcast-address 10.0.0.255; 65option domain-name-servers 10.0.0.1; 66server-name "DHCPserver"; 67server-identifier 10.0.0.1; 68next-server 10.0.0.1; 69 70default-lease-time 120; 71max-lease-time 120; 72 73subnet 10.0.0.0 netmask 255.255.255.0 { 74 filename "pxeboot"; 75 range 10.0.0.10 10.0.0.254; 76 if exists user-class and option user-class = "FreeBSD" { 77 option root-path "tftp://10.0.0.1/FreeBSD"; 78 } 79} 80 81.Ed 82.Va next-server 83is the IP address of the next server in the bootstrap process, i.e. 84your TFTP server or NFS server. 85.Nm 86recognizes 87.Va option root-path 88directives as the server and path to NFS mount for file requests, 89respectively, or the server to make TFTP requests to. 90Note that 91.Nm 92expects to fetch 93.Pa /boot/loader.rc 94from the specified server before loading any other files. 95.Pp 96Valid 97.Va option root-path 98syntax is the following 99.Bl -tag -width <scheme>://ip/path 100.It /path 101path to the root filesystem on the NFS server 102.It ip://path 103path to the root filesystem on the NFS server 104.Ar ip 105.It nfs://path 106path to the root filesystem on the NFS server 107.It nfs://ip/path 108path to the root filesystem on the NFS server 109.Ar ip 110.It tftp://path 111path to the root filesystem on the TFTP server 112.It tftp://ip/path 113path to the root filesystem on the TFTP server 114.Ar ip 115.El 116.Pp 117.Nm 118defaults to a conservative 1024 byte NFS data packet size. 119This may be changed by setting the 120.Va nfs.read_size 121variable in 122.Pa /boot/loader.conf . 123Valid values range from 1024 to 16384 bytes. 124.Pp 125In all other respects, 126.Nm 127acts just like 128.Xr loader 8 . 129.Pp 130For further information on Intel's PXE specifications and Wired for 131Management (WfM) systems, see 132.Li http://www.pix.net/software/pxeboot/archive/pxespec.pdf . 133.Sh SEE ALSO 134.Xr loader 8 135.Sh HISTORY 136The 137.Nm 138bootloader first appeared in 139.Fx 4.1 . 140.Sh AUTHORS 141.An -nosplit 142The 143.Nm 144bootloader was written by 145.An John Baldwin Aq jhb@FreeBSD.org 146and 147.An Paul Saab Aq ps@FreeBSD.org . 148This manual page was written by 149.An Doug White Aq dwhite@FreeBSD.org . 150