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NetBSD 6.1.5 - man page for lpd (netbsd section 8)

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LPD(8)				   BSD System Manager's Manual				   LPD(8)

NAME
     lpd -- line printer spooler daemon

SYNOPSIS
     lpd [-dlsrW] [-b bind-address] [-n maxchild] [-w maxwait] [port]

DESCRIPTION
     lpd is the line printer daemon (spool area handler) and is normally invoked at boot time
     from the rc(8) file.  It makes a single pass through the printcap(5) file to find out about
     the existing printers and prints any files left after a crash.  It then uses the system
     calls listen(2) and accept(2) to receive requests to print files in the queue, transfer
     files to the spooling area, display the queue, or remove jobs from the queue.  In each case,
     it forks a child to handle the request so the parent can continue to listen for more
     requests.

     Available options:

     -b      Normally, if the -s option is not specified, lpd will listen on all network inter-
	     faces for incoming TCP connections.  The -b option, followed by a bind-address spec-
	     ifies that lpd should listen on that address instead of INADDR_ANY.  Multiple -b
	     options are permitted, allowing a list of addresses to be specified.  Use of this
	     option silently overrides the -s option if it is also present on the command line.
	     bind-address can be a numeric host name in IPv4 or IPv6 notation, or a symbolic host
	     name which will be looked up in the normal way.

     -d      The -d option turns on the SO_DEBUG socket(2) option.  See setsockopt(2) for more
	     details.

     -l      The -l flag causes lpd to log valid requests received from the network.  This can be
	     useful for debugging purposes.

     -n      The -n flag sets maxchild as the maximum number of child processes that lpd will
	     spawn.  The default is 32.

     -r      The -r flag allows the ``of'' and ``if'' filters to be used if specified for a
	     remote printer.  Traditionally, lpd would not use filters for remote printers.

     -s      The -s flag selects ``secure'' mode, in which lpd does not listen on a TCP socket
	     but only takes commands from a UNIX domain socket.  This is valuable when the
	     machine on which lpd runs is subject to attack over the network and it is desired
	     that the machine be protected from attempts to remotely fill spools and similar
	     attacks.

     -w      The -w flag sets maxwait as the wait time (in seconds) for dead remote server detec-
	     tion.  If no response is returned from a connected server within this period, the
	     connection is closed and a message logged.  The default is 120 seconds.

     -W      The -W option will instruct lpd not to verify a remote tcp connection comes from a
	     reserved port (<1024).

     If the [port] parameter is passed, lpd listens on this port instead of the usual
     ``printer/tcp'' port from /etc/services.

     Access control is provided by three means.  First, /etc/hosts.allow and /etc/hosts.deny are
     consulted as described in hosts_access(5) with daemon name lpd.  Second, all requests must
     come from one of the machines listed in the file /etc/hosts.equiv or /etc/hosts.lpd unless
     there is a line consisting of '+', in which case any host will be accepted that passes the
     hosts_access(5) test and has reverse resolving set up.  Lastly, if the rs capability is
     specified in the printcap(5) entry for the printer being accessed, lpr requests will only be
     honored for those users with accounts on the machine with the printer.  Requests must pass
     all three tests.

     The file minfree in each spool directory contains the number of disk blocks to leave free so
     that the line printer queue won't completely fill the disk.  The minfree file can be edited
     with your favorite text editor.

     The daemon begins processing files after it has successfully set the lock for exclusive
     access (described a bit later), and scans the spool directory for files beginning with cf.
     Lines in each cf file specify files to be printed or non-printing actions to be performed.
     Each such line begins with a key character to specify what to do with the remainder of the
     line.

     J	     Job Name.	String to be used for the job name on the burst page.

     C	     Classification.  String to be used for the classification line on the burst page.

     L	     Literal.  The line contains identification info from the password file and causes
	     the banner page to be printed.

     T	     Title.  String to be used as the title for pr(1).

     H	     Host Name.  Name of the machine where lpr(1) was invoked.

     P	     Person.  Login name of the person who invoked lpr(1).  This is used to verify owner-
	     ship by lprm(1).

     M	     Send mail to the specified user when the current print job completes.

     f	     Formatted File.  Name of a file to print which is already formatted.

     l	     Like ``f'' but passes control characters and does not make page breaks.

     p	     Name of a file to print using pr(1) as a filter.

     t	     Troff File.  The file contains troff(1) output (cat phototypesetter commands).

     n	     Ditroff File.  The file contains device independent troff output.

     d	     DVI File.	The file contains Tex l output DVI format from Stanford.

     g	     Graph File.  The file contains data produced by plot.

     c	     Cifplot File.  The file contains data produced by cifplot.

     v	     The file contains a raster image.

     o	     The file contains PostScript data.

     r	     The file contains text data with FORTRAN carriage control characters.

     1	     Troff Font R.  Name of the font file to use instead of the default.

     2	     Troff Font I.  Name of the font file to use instead of the default.

     3	     Troff Font B.  Name of the font file to use instead of the default.

     4	     Troff Font S.  Name of the font file to use instead of the default.

     W	     Width.  Changes the page width (in characters) used by pr(1) and the text filters.

     I	     Indent.  The number of characters to indent the output by (in ascii).

     U	     Unlink.  Name of file to remove upon completion of printing.

     N	     File name.  The name of the file which is being printed, or a blank for the standard
	     input (when lpr(1) is invoked in a pipeline).

     If a file cannot be opened, a message will be logged via syslog(3) using the LOG_LPR facil-
     ity.  lpd will try up to 20 times to reopen a file it expects to be there, after which it
     will skip the file to be printed.

     lpd uses flock(2) to provide exclusive access to the lock file and to prevent multiple dae-
     mons from becoming active simultaneously.	If the daemon should be killed or die unexpect-
     edly, the lock file need not be removed.  The lock file is kept in a readable ASCII form and
     contains two lines.  The first is the process id of the daemon and the second is the control
     file name of the current job being printed.  The second line is updated to reflect the cur-
     rent status of lpd for the programs lpq(1) and lprm(1).

FILES
     /etc/printcap		  printer description file
     /var/spool/output/*	  spool directories
     /var/spool/output/*/minfree  minimum free space to leave
     /dev/lp*			  line printer devices
     /var/run/printer		  socket for local requests
     /etc/hosts.allow		  explicit remote host access list.
     /etc/hosts.deny		  explicit remote host denial of service list.
     /etc/hosts.equiv		  lists machine names allowed printer access
     /etc/hosts.lpd		  lists machine names allowed printer access, but not under same
				  administrative control.

SEE ALSO
     lpq(1), lpr(1), lprm(1), setsockopt(2), syslog(3), hosts.equiv(5), hosts_access(5),
     hosts_options(5), printcap(5), lpc(8), pac(8)

     4.3 BSD Line Printer Spooler Manual.

HISTORY
     An lpd daemon appeared in Version 6 AT&T UNIX.

BSD					 January 20, 2006				      BSD
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