1 .\" Copyright (c) 1999 Doug White
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25 .\" $FreeBSD: src/sys/boot/i386/pxeldr/pxeboot.8,v 1.7 2002/12/12 17:25:59 ru Exp $
32 .Nd Preboot Execution Environment (PXE) bootloader
36 bootloader is a modified version of the system third-stage bootstrap
38 configured to run under Intel's Preboot Execution Environment (PXE) system.
39 PXE is a form of smart boot ROM, built into Intel EtherExpress Pro/100 and
40 3Com 3c905c Ethernet cards, and Ethernet-equipped Intel motherboards.
41 PXE supports DHCP configuration and provides low-level NIC access services.
44 bootloader retrieves the kernel, modules,
45 and other files either via NFS over UDP.
46 In combination with a NFS-mounted root file system,
49 EEPROM-burner free construction of diskless machines.
53 binary is loaded just like any other boot file,
54 by specifying it in the DHCP server's configuration file.
55 Below is a sample configuration for the ISC DHCP v2 server:
56 .Bd -literal -offset indent
57 option domain-name "example.com";
58 option routers 10.0.0.1;
59 option subnet-mask 255.255.255.0;
60 option broadcast-address 10.0.0.255;
61 option domain-name-servers 10.0.0.1;
62 server-name "DHCPserver";
63 server-identifier 10.0.0.1;
65 default-lease-time 120;
68 subnet 10.0.0.0 netmask 255.255.255.0 {
69 filename "boot/pxeboot";
70 range 10.0.0.10 10.0.0.254;
71 option root-path "10.0.0.1:/netbootroot";
76 defaults to a conservative 1024 byte NFS data packet. This may be changed
82 Valid values range from 1024 to 4096 bytes.
89 directives as the server and path to NFS mount for file requests,
90 respectively, or the server to make TFTP requests to.
95 from the specified server before loading any other files.
99 .Pa /boot/kernel.BOOTP
101 .Pa /boot/loader-bootp.conf
103 .Pa nextboot-bootp.conf
107 .Pa /boot/loader.conf .
108 Note that the TFTP version
110 uses the standard boot loader files.
111 The NFS version uses different files to allow BOOTP boots via NFS to
112 be overloaded onto the same directory structure as a normal boot,
113 though many other changes would have to be made to actually make
115 However, this is more for historical reasons.
116 Current day PXE boot code can handle complex root-path specifications
117 allowing the root image to be contained in a sub-directory of the NFS
120 In all other respects,
125 As PXE is still in its infancy, some firmware versions may not work
129 bootloader has been extensively tested on version 0.99 of Intel firmware;
130 pre-release versions of the newer 2.0 firmware are known to have
132 Check with the device's manufacturer for their latest stable release.
134 For further information on Intel's PXE specifications and Wired for
135 Management (WfM) systems, see
136 .Pa http://developer.intel.com/ial/wfm/ .
138 .Bl -tag -width ".Pa /boot/defaults/loader-bootp.conf" -compact
139 .It Pa /boot/kernel.BOOTP
142 .It Pa /boot/defaults/loader-bootp.conf
144 configuration file -- do not change this file.
145 .It Pa /boot/loader-bootp.conf
150 .Xr dhcpd 8 Pq Pa net/isc-dhcp42-server ,
159 bootloader first appeared in
165 bootloader was written by
166 .An John Baldwin Aq Mt jhb@FreeBSD.org
168 .An Paul Saab Aq Mt ps@FreeBSD.org .
169 This manual page was written by
170 .An Doug White Aq Mt dwhite@FreeBSD.org .