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PXEBOOT(8)              FreeBSD System Manager's Manual             PXEBOOT(8)

     pxeboot -- Preboot Execution Environment (PXE) bootloader

     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 pro-
     vides low-level NIC access services.  The pxeboot bootloader retrieves
     the kernel, modules, and other files either via NFS over UDP or by TFTP,
     selectable through compile-time options.  In combination with a memory
     file system image or 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 configura-
     tion for the ISC DHCP v2 server:

           option domain-name "";
           option routers;
           option subnet-mask;
           option broadcast-address;
           option domain-name-servers;
           server-name "DHCPserver";

           default-lease-time 120;
           max-lease-time 120;

           subnet netmask {
                  filename "pxeboot";

     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/loader.rc from the specified server before loading any other files.

     In all other respects, pxeboot acts just like loader(8).

     As PXE is still in its infancy, some firmware versions may not work prop-
     erly.  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 Man-
     agement (WfM) systems, see


     The pxeboot bootloader first appeared in FreeBSD 4.1.

     The pxeboot bootloader was written by John Baldwin <> and
     Paul Saab <>.  This manual page was written by Doug White

FreeBSD 6.2                       May 1, 2000                      FreeBSD 6.2


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