bootp(8) bootp(8)
NAME
bootp, bootpgw, in.bootp, in.bootpgw - Internet Boot Protocol
server/gateway
SYNOPSIS
in.bootp [-i -s -t timeout -d level -c chdir-path]
[bootptab [dumpfile]]
in.bootpgw [-i -s -t timeout -d level] server
DESCRIPTION
in.bootp implements an Internet Bootstrap Protocol (BOOTP) server as
defined in RFC951, RFC1532, and RFC1533. in.bootpgw implements a sim-
ple BOOTP gateway which can be used to forward requests and responses
between clients on one subnet and a BOOTP server (i.e. in.bootp) on
another subnet. While either in.bootp or in.bootpgw will forward
BOOTREPLY packets, only in.bootpgw will forward BOOTREQUEST packets.
One host on each network segment is normally configured to run either
in.bootp or in.bootpgw from inetd by including one of the following
lines in the file /etc/inet/inetd.conf:
bootp dgram udp wait root /usr/sbin/in.bootp in.bootp
bootp dgram udp wait root /usr/sbin/in.bootpgw in.bootpgw server
This mode of operation is referred to as "inetd mode" and causes
in.bootp (or in.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).
It is also possible to run in.bootp (or in.bootpgw) in "standalone
mode" (without inetd) by simply invoking it from a shell like any
other regular command. Standalone mode is particularly useful when
in.bootp 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
in.bootp from within /etc/rc.local, for example.) Standalone mode is
less useful for bootpgw 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 respec-
tively (see OPTIONS).
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bootp(8) bootp(8)
OPTIONS
-t timeout
Specifies the timeout value (in minutes) that a in.bootp or
in.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 stan-
dalone mode, this option is forced to zero.
-d debug-level
Sets the debug-level variable that controls the amount of debug-
ging messages generated. For example, -d4 or -d 4 will set the
debugging level to 4. For compatibility with older versions of
in.bootp, omitting the numeric parameter (i.e. just -d) will sim-
ply increment the debug level by one.
-c chdir-path
Sets the current directory used by in.bootp while checking the
existence and size of client boot files. This is useful when
client boot files are specified as relative pathnames, and
in.bootp needs to use the same current directory as the TFTP
server (typically /tftpboot). This option is not recognized by
in.bootpgw.
-i Force inetd mode. This option is obsolete, but remains for compa-
tibility with older versions of in.bootp.
-s Force standalone mode. This option is obsolete, but remains for
compatibility with older versions of in.bootp.
bootptab
Specifies the name of the configuration file from which in.bootp
loads its database of known clients and client options (in.bootp
only).
dumpfile
Specifies the name of the file that in.bootp will dump its inter-
nal database into when it receives a SIGUSR1 signal (in.bootp
only).
server
Specifies the name of a BOOTP server to which in.bootpgw will
forward all BOOTREQUEST packets it receives (in.bootpgw only).
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bootp(8) bootp(8)
OPERATION
in.bootp and in.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 in.bootpgw is started, it determines the address of a BOOTP
server whose name is provided as a command line parameter. When
in.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 in.bootp is started it reads a configuration file, (normally
/etc/inet/bootptab) that initializes the internal database of known
clients and client options. This internal database is reloaded from
the configuration file when in.bootp receives a hangup signal (SIGHUP)
or when it discovers that the configuration file has changed.
When in.bootp receives a BOOTREQUEST packet, it looks for a database
entry matching the client request. If the client is known, in.bootp
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 >
0).
If in.bootp receives a SIGUSR1 signal, it dumps its internal database
to the file /etc/inet/bootpd.dump or the dumpfile specified as a com-
mand line parameter.
During initialization, both programs determine the UDP port numbers to
be used by calling getservbyname(3N) (which normally uses
/etc/services). Two service names (and port numbers) are used:
bootp BOOTP Server listening port
bootpc BOOTP Client destination port
If the port numbers cannot be determined using getservbyname(3N) then
the values default to bootp=67 and bootpc=68.
NOTES
Individual host entries must not exceed 1024 characters.
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bootp(8) bootp(8)
FILES
/etc/inet/bootptab
Database file read by in.bootp
/etc/inet/bootpd.dump
Debugging dump file created by in.bootp
/etc/services
Internet service numbers
/tftpboot
Current directory typically used by the TFTP server and in.bootp
SEE ALSO
inetd(1M), tftpd(1M), bootptab(5).
REFERENCES
DARPA Internet Request For Comments:
RFC951 Bootstrap Protocol
RFC1532 Clarifications and Extensions for the Bootstrap Protocol
RFC1533 DHCP Options and BOOTP Vendor Extensions
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