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.\" $FreeBSD$ 26.\" 27.Dd February 15, 2021 28.Dt PXEBOOT 8 29.Os 30.Sh NAME 31.Nm pxeboot 32.Nd Preboot Execution Environment (PXE) bootloader 33.Sh DESCRIPTION 34The 35.Nm 36bootloader is a modified version of the system third-stage bootstrap 37.Xr loader 8 38configured to run under Intel's Preboot Execution Environment (PXE) system. 39PXE is a form of smart boot ROM, built into Intel EtherExpress Pro/100 and 403Com 3c905c Ethernet cards, and Ethernet-equipped Intel motherboards. 41PXE supports DHCP configuration and provides low-level NIC access services. 42.Pp 43The DHCP client will set a DHCP user class named 44.Va FreeBSD 45to allow flexible configuration of the DHCP server. 46.Pp 47The 48.Nm 49bootloader retrieves the kernel, modules, 50and other files either via NFS over UDP or by TFTP, 51selectable through compile-time options. 52In combination with a memory file system image or NFS-mounted root file system, 53.Nm 54allows for easy, 55EEPROM-burner free construction of diskless machines. 56.Pp 57The 58.Nm 59binary is loaded just like any other boot file, 60by specifying it in the DHCP server's configuration file. 61Below is a sample configuration for the ISC DHCP v3 server: 62.Bd -literal -offset indent 63option domain-name "example.com"; 64option routers 10.0.0.1; 65option subnet-mask 255.255.255.0; 66option broadcast-address 10.0.0.255; 67option domain-name-servers 10.0.0.1; 68server-name "DHCPserver"; 69server-identifier 10.0.0.1; 70next-server 10.0.0.1; 71 72default-lease-time 120; 73max-lease-time 120; 74 75subnet 10.0.0.0 netmask 255.255.255.0 { 76 filename "pxeboot"; 77 range 10.0.0.10 10.0.0.254; 78 if exists user-class and option user-class = "FreeBSD" { 79 option root-path "tftp://10.0.0.1/FreeBSD"; 80 } 81} 82 83.Ed 84.Va next-server 85is the IP address of the next server in the bootstrap process, i.e. 86your TFTP server or NFS server. 87.Nm 88recognizes 89.Va option root-path 90directives as the server and path to NFS mount for file requests, 91respectively, or the server to make TFTP requests to. 92Note that 93.Nm 94expects to fetch 95.Pa /boot/loader.rc 96from the specified server before loading any other files. 97.Pp 98Valid 99.Va option root-path 100syntax is the following 101.Bl -tag -width <scheme>://ip/path 102.It /path 103path to the root filesystem on the NFS server 104.It ip://path 105path to the root filesystem on the NFS server 106.Ar ip 107.It nfs://path 108path to the root filesystem on the NFS server 109.It nfs://ip/path 110path to the root filesystem on the NFS server 111.Ar ip 112.It tftp://path 113path to the root filesystem on the TFTP server 114.It tftp://ip/path 115path to the root filesystem on the TFTP server 116.Ar ip 117.El 118.Pp 119.Nm 120defaults to a conservative 1024 byte NFS data packet size. 121This may be changed by setting the 122.Va nfs.read_size 123variable in 124.Pa /boot/loader.conf . 125Valid values range from 1024 to 16384 bytes. 126.Pp 127In all other respects, 128.Nm 129acts just like 130.Xr loader 8 . 131.Pp 132For further information on Intel's PXE specifications and Wired for 133Management (WfM) systems, see 134.Li http://www.pix.net/software/pxeboot/archive/pxespec.pdf . 135.Sh SEE ALSO 136.Xr loader 8 137.Sh HISTORY 138The 139.Nm 140bootloader first appeared in 141.Fx 4.1 . 142.Sh AUTHORS 143.An -nosplit 144The 145.Nm 146bootloader was written by 147.An John Baldwin Aq jhb@FreeBSD.org 148and 149.An Paul Saab Aq ps@FreeBSD.org . 150This manual page was written by 151.An Doug White Aq dwhite@FreeBSD.org . 152