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       bootpd, bootpgw - Internet Boot Protocol server/gateway


       bootpd  [ -v ] [ -i -s -t timeout -d level -c chdir-path ] [ bootptab [
       dumpfile ] ]
       bootpgw [ -v ] [ -i -s -t timeout -d level ] server


       Bootpd implements an Internet  Bootstrap  Protocol  (BOOTP)  server  as
       defined in RFC951, RFC1532, and RFC1533. This server also provides some
       extension to support the static  part  of  Dynamic  Host  Configuration
       Protocol (DHCP) as specified in RFC1533. DHCP is used by Windows NT and
       95.  Bootpgw implements a simple BOOTP gateway which  can  be  used  to
       forward  requests  and  responses  between  clients on one subnet and a
       BOOTP server (i.e.  bootpd) on another subnet. While either  bootpd  or
       bootpgw  will  forward  BOOTREPLY  packets,  only  bootpgw will forward
       BOOTREQUEST packets.

       One host on each network segment is normally configured to  run  either
       bootpd or bootpgw from inetd by including one of the following lines in
       the file /etc/inetd.conf:

              bootps dgram udp wait root /usr/sbin/bootpd bootpd bootptab
              bootps dgram udp wait root /usr/sbin/bootpgw bootpgw server

       This mode of operation is referred to as "inetd mode" and causes bootpd
       (or  bootpgw)  to  be  started only when a boot request arrives.  If it
       does not receive another packet within fifteen minutes of the last  one
       it  received, it will exit to conserve system resources.  The -t option
       controls this timeout (see OPTIONS below).

       It is also possible to run bootpd (or  bootpgw)  in  "standalone  mode"
       (without  inetd)  by  simply  invoking  it  from a shell like any other
       regular command.  Standalone mode is particularly useful when bootpd is
       used  with  a  large  configuration  database, where the start up delay
       might otherwise prevent timely response to client requests.  (Automatic
       start  up in standalone mode can be done by invoking bootpd from within
       /etc/rc.local, for example.)  Standalone mode is less useful for bootgw
       which  has  very  little  start  up  delay  because  it does not read a
       configuration file.

       Either program automatically detects whether it was invoked from  inetd
       or from a shell and automatically selects the appropriate mode.  The -s
       or -i option may be used to force standalone or inetd mode respectively
       (see OPTIONS).


       -t timeout
              Specifies  the  timeout  value  (in  minutes)  that  a bootpd or
              bootpgw process will wait for a BOOTP packet before exiting.  If
              no  packets  are  received for timeout seconds, then the program
              will exit.  A timeout value of zero  means  "run  forever".   In
              standalone mode, this option is forced to zero.

       -d debug-level
              Sets  the  debug-level  variable  that  controls  the  amount of
              debugging messages generated.  For example, -d4 or -d 4 will set
              the debugging level to 4.  For compatibility with older versions
              of bootpd, omitting the numeric parameter (i.e.  just  -d)  will
              simply increment the debug level by one.

       -c chdir-path
              Sets  the  current  directory  used by bootpd while checking the
              existence and size of client boot files.  This  is  useful  when
              client  boot  files  are  specified  as  relative pathnames, and
              bootpd needs to use the  same  current  directory  as  the  TFTP
              server  (typically /tftpboot).  This option is not recognized by

       -i     Force inetd mode.  This option  is  obsolete,  but  remains  for
              compatibility with older versions of bootpd.

       -s     Force standalone mode.  This option is obsolete, but remains for
              compatibility with older versions of bootpd.

       -v     Print version and exit.

              Specifies the name of the configuration file from  which  bootpd
              loads  its  database of known clients and client options (bootpd
              only). Default is /etc/bootptab.

              Specifies the name  of  the  file  that  bootpd  will  dump  its
              internal database into when it receives a SIGUSR1 signal (bootpd
              only).  This option is only recognized if  bootpd  was  compiled
              with the -DDEBUG flag.

       server Specifies  the  name  of  a  BOOTP  server to which bootpgw will
              forward all BOOTREQUEST packets it receives (bootpgw only).


       Both bootpd and bootpgw operate similarly in that both listen  for  any
       packets  sent to the bootps port, and both simply forward any BOOTREPLY
       packets.  They differ in their handling of BOOTREQUEST packets.

       When bootpgw is started, it determines the address of  a  BOOTP  server
       whose  name  is  provided  as  a  command line parameter.  When bootpgw
       receives a BOOTREQUEST packet, it sets the "gateway address"  and  "hop
       count" fields in the packet and forwards the packet to the BOOTP server
       at the address determined earlier.  Requests are forwarded only if they
       indicate that the client has been waiting for at least three seconds.

       When  bootpd  is  started  it  reads  a  configuration  file, (normally
       /etc/bootptab) that initializes the internal database of known  clients
       and  client  options.   This  internal  database  is  reloaded from the
       configuration file when bootpd receives a  hangup  signal  (SIGHUP)  or
       when  it  discovers that the configuration file has changed.  Note that
       any changes to the configuration file should be atomic  to  avoid  race

       When  bootpd  receives  a  BOOTREQUEST  packet, it looks for a database
       entry matching the client request.  If  the  client  is  known,  bootpd
       composes  a  BOOTREPLY packet using the database entry found above, and
       sends the reply to the client  (possibly  using  a  gateway).   If  the
       client  is  unknown, the request is discarded (with a notice if debug >

       If bootpd is compiled with the -DDEBUG option,  receipt  of  a  SIGUSR1
       signal   causes   it   to  dump  its  internal  database  to  the  file
       /tmp/bootpd.dump or the dumpfile specified as a command line parameter.

       During  initialization, both programs determine the UDP port numbers to
       be   used   by   calling   getservbyname(3)   (which   normally    uses
       /etc/services).  Two service names (and port numbers) are used:

              bootps - BOOTP Server listening port
              bootpc - BOOTP Client destination port

       If  the  port numbers cannot be determined using getservbyname then the
       values default to boopts=67 and bootpc=68.


              Database file read by bootpd.

              Debugging dump file created by bootpd.

              Internet service numbers.

              Current directory typically used by the TFTP server and  bootpd.


       Individual host entries must not exceed 1024 characters.


       This   distribution   is   currently  maintained  by  Walter  L.  Wimer

       The original BOOTP  server  was  created  by  Bill  Croft  at  Stanford
       University in January 1986.

       The  current  version  of  bootpd is primarily the work of David Kovar,
       Drew D. Perkins, and Walter L. Wimer, at Carnegie Mellon University.

       Enhancements and bug-fixes have been contributed by:
              (in alphabetical order)
              Danny Backx <>
              John Brezak <>
              Frank da Cruz <>
              David R. Linn <>
              Jim McKim <>
              Pauline Middelink <>
              Martin Schulze <>
              Gordon W. Ross <>
              Jason Zions <>


       bootptab(5), services(5), inetd(8), inetd.conf(5), tftpd(8).

       DARPA Internet Request For Comments:

       RFC951    Bootstrap Protocol

       RFC1532   Clarifications and Extensions for the Bootstrap Protocol

       RFC1533   DHCP Options and BOOTP Vendor Extensions