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PXEBOOT(8) DragonFly System Manager's Manual PXEBOOT(8)
NAME
pxeboot - Preboot Execution Environment (PXE) bootloader
DESCRIPTION
The pxeboot bootloader is a modified version of the system third-stage
bootstrap loader(8) configured to run under Intel's Preboot Execution
Environment (PXE) system. PXE is a form of smart boot ROM, built into
Intel EtherExpress Pro/100 and 3Com 3c905c Ethernet cards, and Ethernet-
equipped Intel motherboards. PXE supports DHCP configuration and
provides low-level NIC access services. The pxeboot bootloader retrieves
the kernel, modules, and other files either via NFS over UDP. In
combination with a NFS-mounted root file system, pxeboot allows for easy,
EEPROM-burner free construction of diskless machines.
The pxeboot binary is loaded just like any other boot file, by specifying
it in the DHCP server's configuration file. Below is a sample
configuration for the ISC DHCP v2 server:
option domain-name "example.com";
option routers 10.0.0.1;
option subnet-mask 255.255.255.0;
option broadcast-address 10.0.0.255;
option domain-name-servers 10.0.0.1;
server-name "DHCPserver";
server-identifier 10.0.0.1;
default-lease-time 120;
max-lease-time 120;
subnet 10.0.0.0 netmask 255.255.255.0 {
filename "boot/pxeboot";
range 10.0.0.10 10.0.0.254;
option root-path "10.0.0.1:/netbootroot";
}
pxeboot defaults to a conservative 1024 byte NFS data packet. This may
be changed by setting the nfs.read_size variable in /boot/loader.conf.
Valid values range from 1024 to 4096 bytes.
pxeboot recognizes next-server and option root-path directives as the
server and path to NFS mount for file requests, respectively, or the
server to make TFTP requests to. Note that pxeboot expects to fetch
/boot/dloader.rc from the specified server before loading any other
files.
pxeboot uses /boot/kernel.BOOTP and /boot/loader-bootp.conf instead of
/boot/kernel and /boot/loader.conf. Note that the TFTP version
pxeboot_tftp(8) uses the standard boot loader files. The NFS version
uses different files to allow BOOTP boots via NFS to be overloaded onto
the same directory structure as a normal boot, though many other changes
would have to be made to actually make that work. However, this is more
for historical reasons. Current day PXE boot code can handle complex
root-path specifications allowing the root image to be contained in a
sub-directory of the NFS export.
In all other respects, pxeboot acts just like loader(8).
As PXE is still in its infancy, some firmware versions may not work
properly. The pxeboot bootloader has been extensively tested on version
0.99 of Intel firmware; pre-release versions of the newer 2.0 firmware
are known to have problems. Check with the device's manufacturer for
their latest stable release.
For further information on Intel's PXE specifications and Wired for
Management (WfM) systems, see http://developer.intel.com/ial/wfm/.
FILES
/boot/kernel.BOOTP Default kernel for pxeboot.
/boot/defaults/loader-bootp.conf pxeboot configuration file -- do
not change this file.
/boot/loader-bootp.conf pxeboot configuration file.
SEE ALSO
dhcpd(8) (net/isc-dhcp42-server), diskless(8), loader(8), nfsd(8),
pxeboot_tftp(8), tftpd(8)
HISTORY
The pxeboot bootloader first appeared in FreeBSD 4.1.
AUTHORS
The pxeboot bootloader was written by John Baldwin <jhb@FreeBSD.org> and
Paul Saab <ps@FreeBSD.org>. This manual page was written by Doug White
<dwhite@FreeBSD.org>.
DragonFly 6.1-DEVELOPMENT November 1, 2019 DragonFly 6.1-DEVELOPMENT