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 May 25, 2017 26.Dt PXEBOOT 5 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 5 36configured to run under Intel's Preboot Execution Environment (PXE) system. 37PXE is a form of smart boot ROM, built into Ethernet cards, and 38Ethernet-equipped motherboards. 39PXE supports DHCP configuration and provides low-level NIC access services. 40The 41.Nm 42bootloader retrieves the kernel, modules, 43and other files either via NFS over UDP or by TFTP, 44selectable through DHCP options. 45.Pp 46The 47.Nm 48binary is loaded just like any other boot file, 49by specifying it in the DHCP server's configuration file. 50Below is a sample configuration for the ISC DHCP v2 server: 51.Bd -literal -offset indent 52option domain-name "example.com"; 53option routers 10.0.0.1; 54option subnet-mask 255.255.255.0; 55option broadcast-address 10.0.0.255; 56option domain-name-servers 10.0.0.1; 57server-name "DHCPserver"; 58server-identifier 10.0.0.1; 59 60default-lease-time 120; 61max-lease-time 120; 62 63subnet 10.0.0.0 netmask 255.255.255.0 { 64 filename "pxeboot"; 65 range 10.0.0.10 10.0.0.254; 66} 67 68.Ed 69.Pp 70.Nm 71recognizes 72.Va next-server 73and 74.Va option root-path 75directives as the server and path to NFS mount for file requests, 76respectively, or the server to make TFTP requests to. 77Note that 78.Nm 79expects to fetch 80.Pa /boot/loader.rc 81from the specified server before loading any other files. 82.Pp 83.Nm 84defaults to a conservative 1024 byte NFS data packet size. 85This may be changed by setting the 86.Va nfs.read_size 87variable in 88.Pa /boot/loader.conf . 89Valid values range from 1024 to 16384 bytes. 90.Pp 91.Nm 92chooses NFS or TFTP based on the value of 93.Va root-path 94variable provided by the DHCP server. 95.Nm 96defaults to use NFS if the 97.Va root-path 98variable is in the 99.Qq Pa ip-address Ns :/ Ns Pa path 100form, otherwise TFTP is used. 101.Pp 102TFTP block size can be controlled by setting the 103.Va tftp.blksize 104variable in 105.Pa /boot/loader.conf . 106Valid values range from 8 to 9008 bytes. 107.Pp 108In all other respects, 109.Nm 110acts just like 111.Xr loader 5 . 112.Pp 113For further information on Intel's PXE specifications and Wired for 114Management (WfM) systems, see 115.Li http://www.intel.com/design/archives/wfm/ . 116.Sh SEE ALSO 117.Xr loader 5 118