bootpd(1M) bootpd(1M)
NAME
bootpd - Internet Boot Protocol server
SYNOPSIS
in.bootpd [-i -s -ttimeout -dlevel -cchdir-path] [bootptab [dumpfile]]
in.bootpgw [-i -s -ttimeout -dlevel] server
DESCRIPTION
The bootpd command implements an Internet Bootstrap Protocol
(BOOTP) server as defined in RFC951, RFC1532, and RFC1533.
The bootpgw command implements a simple BOOTP gateway which
can be used to forward requests and responses between clients
on one subnet and a BOOTP server on another subnet. While
either bootpd or bootpgw will forward BOOTREPLY packets, only
bootpgw will forward BOOTREQUEST packets.
Files
/etc/inet/bootptab data base file read by bootpd
/etc/inet/bootpd.dump debugging dump file created by bootpd
/etc/inet/config Internet networking services
configuration file
/etc/inet/services Internet service numbers
tftpboot current directory typically used by
the TFTP server and bootpd
USAGE
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/inet/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 bootpd 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.
It is also possible to run bootpd (or bootpgw) in ``standalone
mode'' (that is, 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 data base, where the startup delay might
otherwise prevent timely response to client requests. Note
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bootpd(1M) bootpd(1M)
that automatic startup in standalone mode can be performed by
invoking bootpd from within /etc/inet/config, for example.
Standalone mode is less useful for bootpgw, which has very
little startup delay because it does not read a configuration
file.
Either command 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.
The bootptab argument specifies the name of the configuration
file from which bootpd loads its data base of known clients
and client options. This argument is not recognized by
bootpgw.
The dumpfile argument specifies the name of the file into
which bootpd dumps its internal data base when it receives a
SIGUSR1 signal. This argument is only recognized if bootpd
was compiled with the -DDEBUG flag. This argument is not
recognized by bootpgw.
The server argument specifies the name of a BOOTP server to
which bootpgw forwards all BOOTREQUEST packets it receives.
This argument is not recognized by bootpd.
Options
bootpd and bootpgw take the following options:
-t timeout
Specifies, in minutes, the timeout value that a bootpd
or bootpgw process will wait for a BOOTP packet before
exiting. If no packets are received for timeout
seconds, then the daemon will exit. A timeout value of
zero means ``run forever.'' In standalone mode, this
option is forced to zero.
-d level
Sets the debug variable that controls the amount of
debugging messages generated to level. For example, -d4
or -d 4 will set the debugging level to 4. For
compatibility with older versions of bootpd, omitting
the numeric parameter (that is, by using just -d)
increments the debug level by one.
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bootpd(1M) bootpd(1M)
-c chdir-path
Sets the current directory used by bootpd while checking
the existence and size of client boot files to chdir-
path. This option 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 bootpgw.
-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.
Operation
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
(typically /etc/inet/bootptab) that initializes the internal
data base of known clients and client options. This internal
data base is reloaded from the configuration file when bootpd
receives the hangup signal SIGHUP, or when it discovers that
the configuration file has changed (bootpd checks the
modification date for each request).
Note that the UnixWare version of bootpd has the capability to
respond to UnixWare clients even if no explicit entry exists
for the requesting client. See bootptab(4) for details.
When bootpd receives a BOOTREQUEST packet, it checks the
modification time of the configuration file and reloads the
data base if necessary. Then it looks for a data base entry
matching the client request. If the client is known, bootpd
composes a BOOTREPLY packet using the data base entry found
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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 bootpd is compiled with the -DDEBUG option, receipt of a
SIGUSR1 signal causes it to dump its internal data base to the
file /etc/inet/bootpd.dump or to the dumpfile specified as a
command line argument.
During initialization, both bootpd and bootpgw determine the
UDP port numbers to be used by calling getservbyname (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 bootps=67 and bootpc=68.
REFERENCES
bootp(1M), bootptab(4), config(4), inetd(1M)
RFC951, RFC1532, RFC1533
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