LPD.CONF(5)

📦 version 3.8.B, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

✨ NAME ✨

lpd.conf — the configuration file for the LPRng line printer spooler system, bestie. This is the manual page, LPD.CONF(5), filed under File Formats Manual, and it's literally the glow-up guide for your whole print setup. 🎀

🌸 DESCRIPTION 🌸

okay so here's the tea: the file lpd.conf is what you use to hand over configuration info to the LPRng Printer spooler system, and it also sets the defaults for printcap information. 💖

The parsing rules are giving very chill, very forgiving:

  • Leading spaces on lines? Ignored, we don't care. 🫶
  • Blank lines? Ignored. 💤
  • Lines whose first nonblank character is a sharp (#)? Also ignored, that's a comment bestie. 🙈

Trailing blanks and tabs (whitespace) on an option value get deleted — UNLESS the last one is escaped with a backslash (\). Then it stays. 💅

Every other line specifies parameters, and it should look like one of these:

keyword
keyword@
keyword#value
keyword=value

Not me reminding you that these values are the same format as printcap(5) values. iykyk. ✨

So here's the cute part: values in the configuration can contain host or machine dependent information. To help with that, these escape sequences in the configuration information get replaced like so:

  • %h — the short form of the host name (i.e. non fully qualified). 🦋
  • %H — the fully qualified host name. 💜
  • %a — the abbreviated architecture name, like sun4, sol2, hpux, aix, irix5, etc. This value can be set using the architecture keyword in the configuration file, and it's set to a default value at compile_time. ⭐
  • %P — the printer name from the printcap entry (see below). 🎀
  • %R — the remote printer name from the printcap entry. 🌈
  • %M — the remote host name from the printcap entry. This is truncated to the short host name. 🌸

For example, on host dickory.sdsu.edu, the strings short=%h long=%H arch=%a would be expanded as short=dickory long=dickory.sdsu.edu arch=sun4 . no cap. 💅

The P, R, and M tags are provided for use with combined configuration and printcap information. But heads up: these values are not expanded when the printcap information is initially processed, and can be used only in a limited number of printcap or other entries. Currently only the printcap :sd: (spool directory) and :forward_server: (forward server) entries use these. 🫶

💖 GENERAL CONFIGURATION PARAMETERS 💖

Some of the following parameters take lists of files or directories. Unless otherwise explicitly stated, these lists can be separated by commas (,), semicolons (;), or colons, (punctuation) and possibly tabs or spaces (whitespace) as well. mix and match, she's flexible. 🦋

Keyword names can use either underscores (_) or hyphens (-) in their names, but the underscore is preferred. periodt. 💅

  • include pathname [pathname*] (no default) — This can be used to include files into the lpd.conf file. The include file parameter a whitespace separated list of files; the files must have absolute pathnames and must be readable. 👑
  • ae (default: "jobend $H $n $P $k $b $t") — This specifies either a script or a filter to be invoked at the send of a job for accounting purposes. See as for the matching accounting at start, and the printcap(5) and lpd(8) man pages for details. 🧾
  • allow_getenv (default: "LPD_CONF") — This option specifies an environment variable whose value is a configuration file. Use of this is restricted to test purposes, and SUID ROOT client and server will not run when the variable is enabled. so like, don't. 💀
  • ar (default: yes) — See printcap(5) for details. ✨
  • architecture — The default value is set at compile time and can be overwritten with this parameter. The default value of this parameter is set at compile time and it is used when expanding the special sequence %a in pathname and filename strings in this config file. 🏗️
  • auth (default: NULL) — Authentication type to be used for client to server communication. 🔐
  • auth_client_filter (default: NULL) — Program to be used for client to server communication. 🫶
  • auth_forward (default: NULL) — Authentication type to be used for server to server communication. 🔐
  • auth_forward_filter (default: NULL) — Program to be used for server to server communication. 📡
  • auth_forward_id (default: NULL) — Authentication id of remote server for server to server communication. 🆔
  • auth_receive_filter (default: NULL) — Program to be used by server receive server or client communication. 📬
  • auth_server_id (default: NULL) — Authentication id of originating client or server. 🪪
  • as (default: "jobstart $H $n $P $k $b $t") — See as. 👀
  • bk (default: no) — See printcap(5) for details. 📖
  • bk_filter_options (default: "$P $w $l $x $y $F $c $L $i $J $C $0n $0h $-a") — If the "bkf" (backwards compatible filter) flags is set in the printcap entry and the original filter specification does not have a `$` in it, this option string is appended to a filter specification, and the string expanded with values from the printcap information and job information. (see of_filter_options, filter_options, bk_filter_options, bk_of_filter_options) 🔥
  • bk_of_filter_options (default: "$w $l $x $y") — If the "bkf" (backwards compatible filter) flags is set in the printcap entry and the original filter specification does not have a `$` in it, this option string is appended to the OF filter specification, and the string expanded with values from the printcap information and job information. (see of_filter_options, filter_options, bk_filter_options, bk_of_filter_options) 💫
  • check_for_nonprintable (default: "") — (Used by LPR) check f and p formats for non_printable characters unless -b (binary) or -l (literal) command_line option is supplied. Note that files containing HPGL or other printer control languages would often be classed as ``non_printable''. 👀
  • connect_grace (default: 0 seconds) — The time to pause before opening a new connection to a printer. This allows the printer time to recover from the previous job. give her a sec, she's resting. 😌
  • connect_interval (default: 10 (seconds)) — The time to pause after a failed connection or open of the printing device before attempting a new connection or open. 🔁
  • connect_timeout (default: 10 (seconds)) — The time to wait for a device open or connection to complete. A zero value is infinite timeout. ⏳
  • retry_nolink (default: true) — When TRUE and the LPD server is printing or transferring a job, then an indefinite number of attempts to connect to or open the IO device will be made. she does NOT give up, main character energy. 💪
  • default_banner_printer (default: "") — The default banner printer program to be used for printing banners. This should be specified in the LPD configuration file. 🎏
  • default_format (default: "f") — Default format for printing jobs. 📄
  • default_logger_port (default: 2001) — specifies a default port number for logger information. See logger_destination for details. 📊
  • default_logger_protocol (default: UDP) — specifies a default protocol for logger information. See logger_destination for details. 📡
  • default_permission (default: ACCEPT) — Default permission for operations. ✅
  • default_printer (default: "") — The default printer to use if there is no PRINTER environment variable, the user has not specified a printer, or there is no printcap information. 🖨️
  • default_priority (default: "A") — Default priority (class) for printing jobs. This is also used as the job class. ⭐
  • default_remote_host (default: "%H") — The default remote host to use. 🌐
  • default_tmp_dir (default: /tmp) — Directory for temporary files. 📁
  • domain_name (default: "") — This parameter is optional, and is appended to the hostname to make it into a fully_qualified domain name, ie. class.iona.ie. It will only be used if the software cannot determine the domain name using other means, such as gethostbyname(3n). 🏠
  • ff (default: \f) — Formfeed string. 📃
  • filter_ld_path (default: ) — The value for the environment variable LD_LIBRARY_PATH, both used when executing, and passed on to filters. This variable is used to find shared libraries on SunOS, Solaris and Linux. 🧚
  • filter_options (default: "$C $F $H $J $L $P $Q $R $Z $a $c $d $e $f $h $i $j $k $l $n $p $r $s $w $x $y $-a") — If the "bkf" (backwards compatible filter) flags is not set in the printcap entry and the original filter specification does not have a `$` in it, this option string is appended to a filter specification, and the string expanded with values from the printcap information and job information. (see of_filter_options, filter_options, bk_filter_options, bk_of_filter_options) 🌟
  • filter_path (default: /bin:/usr/bin:/usr/local/bin) — The value for the environment variable PATH, both used to find filters and passed on to filters run by lpd and lpr. 🛣️
  • force_poll (default: no) — Some software packages put print jobs directly into the spool queues. The force_poll flag forces lpd to periodically poll spool queues looking for jobs and no server. The poll_time variable sets the interval between polls. 🕵️
  • full_time (default: no) — Use full time and date format in logging and error messages. 🕰️
  • fx (default: "") — See printcap(5) for details. This specifies the job formats allowed for this queue. 🎯
  • group (default "daemon") — The group to use for file ownership and process permissions. Used only by lpd; this can be the name of a group or a number. All filters will run as the specified group. Note that if the group value is 0, then the real user group of the process at startup will be used. 👥
  • kerberos_keytab (default "/etc/lpd.keytab") — The keytab file to be used by the LPD server when using built-in kerberos authentication. The keytab file should be owned by the LPD server, and be readable/writable only by it (i.e. - 600 permissions). 🔑
  • kerberos_life (default NULL) — The lifetime of a Kerberos ticket. NULL selects the default lifetime. Time should be specified using the standard Kerberos time representations. ⏱️
  • kerberos_forward_principal (default NULL) — remote principal used by server when forwarding 🌉
  • kerberos_renew (default NULL) — The renewal of a Kerberos ticket. NULL selects a non-renewable ticket. Time should be specified using the standard Kerberos time representations. ♻️
  • kerberos_server_principal (default "lpr") — Server principal used when client sending to server or when server is originating connection to another server for forwarding. 👑
  • kerberos_service (default "lpr") — bestie, this is the service name you use when you're making requests to the LPD server with kerberos auth. Like, say kerberos_service is set to lpr, the server lives on host alpha.com, and your kerberos domain is ALPHA.COM — then the kerberos principal name would be:
lpr/alpha.com@ALPHA.COM
  • la (default: yes) — see printcap(5) for the deets.
  • lf (default: log) — the name of the log file. that's it, that's the whole vibe.
  • lo (default: lock) — the name of the lock file.
  • localhost (default "localhost") — the name of the localhost entry used for the TCP/IP loopback interface. The TCP/IP connection may originate from the local host, so use this name to check whether the local host address is in the IP address database, and use it as the origination address for local connections. Why?? because it avoids problems with multi-homed hosts that originate connections from different interfaces. 💅
  • lockfile (default: /var/spool/lpd/lpd) — this is the file that signals "hey, an lpd server is running on this host". The lpd_port value gets appended to the lockfile value so you get a unique lockfile even when different versions of LPRng are running on the same system. no collision drama here 🫶
  • logger_destination (default: "") — this specifies where logger info generated by the lpd server goes. The destination spec is built like host[%port][,(TCP|UDP)]. For example, localhost%2001,UDP would send logger information to the localhost IP address, on port 2001 using the UPD protocol. The default port and protocol come from the default_logger_port and default_logger_protocol configuration variables respectively.
  • longnumber (default: no) — RFC1179 requires 3 digit job numbers; setting longnumber to yes allows 6 digit numbers. If the backwards_compatible flag is set, only 3 digit numbers will be used.
  • lpd_listen_port (default: =off) [ipaddr%]port — the port that lpd binds to. If the parameter is set to off then lpd does not listen to any TCP port. See lpd_port for the details of the format of the argument.

If this is not set at all, then lpdP will listen on lpd_port.

  • lpd_port (default: printer) [ipaddr%]port — the port that lpr and the other client programs send their requests to. The spec has the format ipaddr%port. If the IP address is specified then a bind to only this address and port is done. If the port value is not a number a service lookup is performed and the corresponding service port is used; see services(5). This parameter is lowkey iconic for debugging a new installation of LPRng, because running LPRng on a different port from the default will not interfere with a previous installation of LPD or LPRng. 👑
  • lpd_printcap_path (default: "") — the location of lpd server only printcap database information. If this is nonblank the printcap_pathP will not be used by the lpd server.
  • mail_operator_on_error (default: "") — put this person on the CC-list of the mail, but only if it is not a success mail. (So in addition to the person who made the printer request, this person also gets error messages, but no success messages. imagine.)
  • max_status_line (default: 79) — an integer value specifying the number of characters used for displaying simple job status; this includes the queue position, job identifier, job contents, size, and time. A 0 (zero) value indicates no restrictions.
  • max_status_size (default: 10 (Kbytes)) — an integer value specifying (in K bytes) the maximum size of the status file generated during printing operations. A 0 value will create unlimited size status files. When the file size exceeds this value, it is truncated to min_status_size K bytes.
  • mc (default: 1) — see printcap(5) for details.
  • min_status_size (default: 0 (Kbytes)) — minimum status size. If 0, defaults to 20 percent of max_status_size.
  • minfree (default: 0) — the amount of free space (in Kbytes) needed in the spool directory for a job to even be accepted. If 0, there is no limit; if the parameter is the name of a file rather than a number, the file must contain a numerical minimum free value (in Kbytes). This value is overridden by the printcap mi field value.
  • ms_time_resolution (default: FALSE) — this flag causes the time information to be printed to millisecond accuracy. fr fr this is overkill for most purposes. 😭
  • of_filter_options (default: "") — if this is not set, the value defaults to the same as the filter_options value. This string is appended to a OF filter specification, and the string is expanded with values from the printcap information and job information. If the "bkf" (backwards compatible filter) flags is set in the printcap entry, the bk_of_filter_options value is appended instead (see of_filter_options, filter_options, bk_filter_options, bk_of_filter_options).
  • originate_port (default: "721 731") — a range of port numbers to originate requests from. When sending service requests, the software will try to open and bind to these ports to originate a request to a server. If no port is given, or all of the requested ports are unavailable or cannot be bound to, then a normal use port is requested. Heads up: on UNIX systems, if a port in the range 0-1023 is requested the EUID of the process must be root for the request to be granted. Also note that RFC1179 specifies that requests must originate from ports in the range 721-731.
  • pass_env (default: "LANG,LC_CTYPE,LC_NUMERIC,LC_TIME,LC_COLLATE,LC_MONETARY,LC_MESSAGES,LC_PAPER,LC_NAME,LC_ADDRESS,LC_TELEPHONE,LC_MEASUREMENT,LC_IDENTIFICATION,LC_ALL") — client programs such as LPR, LPC, etc., will pass these environment variables to any filter programs they start. 🦋
  • poll_time (default: 6000) — interval in seconds at which LPD checks for queues with jobs and no server active. See force_poll as well.
  • pl (default: 66) — see printcap(5) for details.
  • pr (default: /bin/pr) — see printcap(5) for details.
  • printcap_path (default: "/etc/printcap") — the location of the printcap database file. If a file or filter does not exist, it is considered a fatal error. All valid entries in these files will be used. See PRINTCAP LOOKUP for details.
  • perms_path (default: /etc/lpd.perms:/usr/etc/lpd.perms:/var/spool/lpd/lpd.perms.%h) — the location of the printer permissions database. If a file or filter does not exist, it is skipped. The first file or filter that exists and is readable will be used. See PERMISSIONS LOOKUP for details.
  • pw (default: 80) — see printcap(5) for details.
  • save_on_error (default: no) — save a job in the spool queue if it has an error rather than removing it.
  • save_when_done (default: no) — save a job in the spool queue after completion rather than removing it.
  • send_data_first (default: no) — send data files of a job first, followed by the control file.
  • send_failure_action (default: "") — the lpd server uses this to decide what to do when it's unable to print or process a job. The keyword abort will cause it to terminate operations, leaving the job in the queue, remove will cause it to remove the job, retry will cause it to retry the job, and hold will cause it to hold the job with an error indication. If the value is a filter, then the filter will be invoked and the exit status of the filter is used to determine the actions.
  • send_job_rw_timeout (default: 6000) — when printing or sending a job to a remote printer, use this as the write to the device or remote host timeout value. If a timeout occurs, then a FAIL status is returned and the send_failure_action value is used to determine what to do on failure.
  • send_try (default: 3) — number of times to try to send a job to the printer or remote host. A 0 value means an infinite number of times. 💀
  • sendmail (default: "/usr/lib/sendmail -oi -t") — if the argument is empty then all mail_related functionality is disabled. The arguments are the command to run when mail is to be sent. The command used needs to be able to accept the message on stdin, with no arguments. The message will contain the To:, From:, Cc: and Subject: headers.
  • server_tmp_dir (default: /tmp) — temporary dir for the server.
  • spool_dir_perms (default: 042700) — permissions of the spool directories.
  • spool_file_perms (default: 0600) — permissions of the spool files.
  • syslog_device (default: /dev/console) — log to this device if all else fails. the backup plan of backup plans 🙈
  • unix_socket_path (default: /var/run/lprng/socket) — location of the Unix socket that lpd listens on and that LPRng clients attempt to communicate to when host is localhost. Set to off to disable listening and connecting via a Unix socket.
  • use_date (default: no) — no information about this parameter available. (not me telling you there's literally nothing in the docs for this one 💅)
  • use_identifier (default: no) — add a job identifier line to the control file, using the 'A' entry in the control file.
  • use_info_cache (default: yes) — if this is set to yes, lpd.perms and printcap information lookups will be cached for later use. Only lookups in the main databases will be cached, not lookups in the per_printer databases. You can force the lpd to flush its cache and reread the permissions file by sending it a SIGHUP. 🎀
  • use_queuename (default: no) — put an entry into control files identifying the spool queue the job was originally sent to. The entry has the form 'Qspoolname', and its value can be passed to filters. This is useful for setting up a spool queue which formats jobs in different ways, depending on the name of the queue.
  • use_shorthost (default: no) — okay so by default, the names of lpr job files use the originating host's fully qualified domain name, right? And bestie, that can go over 14 characters, which is literally the limit for file names on some UNIX systems 😭. Set this to yes and it uses the non-qualified name instead — and if the host name is at most 8 characters, your file name stays at most 14 characters long. slay.
  • user (default: daemon) — this is the user that lpd and its filters run as, and it's also the owner of the spool directories and the other lpd_writable files 🫶. It can be a user name or a number. And if the user value is 0, then the real UID of the program when it was started gets used — which is how a non_root user can test out the functionality of the LRPng software ✨.

🔍 PRINTCAP LOOKUP, DATABASE FILES AND FILTERS 🔍

So the printcap_path and printer_perms_path variables specify a list of either data base files or filters to use to get printcap or permission entries for a printer 👑. To get information, the filter is started and a single line with the printer name is sent to it. And ngl, note that the printer name all is used to request information either about all printers, or about a specific printer entry that has a list of all printers. See printcap(5) for more details 💅.

To find the printcap information, LPRng programs will read the database files specified in the printcap_path entry. The lpd server will read any additional files specified in the lpd_printcap_path entry. And here's the part where you gotta pay attention, bestie:

If any of the files is missing or non-readable, a fatal error will result 💀. No cap.

After having searched the various files, if a filter has been specified, the filter will be started and the required printer name will be sent to the filter. The output from the filter will be used as the printcap information. iconic.

Environment variables are sanitized by lpd and the other executables — like, the variables IFS, LD_PRELOAD and LD_PROFILE are all deleted from the environment passed to filters and any other sub_processes 🧚. For more reliability, script filters should set their own PATH and LD_LIBRARY_PATH variables. fr fr.

All filters will run as the user and group specified by the group and user variables 💜.

🌸 EXAMPLE 🌸

# lpd.conf generated from  on Wed Apr  7 07:59:48 PDT 1999

#   The values in this file are the default values.
#   If you modify the file,  set the value to something other than the default
#   For example, '# default force_localhost' means
#     the 'force_localhost' option value is on or 1.
#   Uncomment this and change it to read 'force_localhost@'

# Purpose: always print banner, ignore lpr -h option
#   default ab@
# Purpose: query accounting server when connected
#   default achk@
# Purpose: accounting at end (see also af, la, ar, as)
#   default ae=jobend $H $n $P $k $b $t
# Purpose: name of accounting file (see also la, ar)
#   default af=
af=acct
# Purpose: automatically hold all jobs
#   default ah@
ah
# Purpose: Allow duplicate command line arguments (legacy requirement)
#   default allow_duplicate_args@

📂 FILES 📂

The files used by LPRng are set by values in the printer configuration file. The following are a commonly used set of default values 🎀.

  • /etc/lprng/lpd.conf — LPRng configuration file
  • ${HOME}/.printcap — user printer description file
  • /etc/printcap — printer description file
  • /etc/lprng/lpd.perms — permissions
  • /var/run/lprng/lpd — lock file for queue control
  • /var/spool/lpd — spool directories
  • /var/spool/lpd/QUEUE/control — queue control
  • /var/spool/lpd/QUEUE/log — trace or debug log file
  • /var/spool/lpd/QUEUE/acct — accounting file
  • /var/spool/lpd/QUEUE/status — status file

👀 SEE ALSO 👀

lpc(8), lpd(8), checkpc(8), lpr(1), lpq(1), lprm(1), printcap(5), lpd.perms(5), pr(1), lprng_certs(1), lprng_index_certs(1).

🩺 DIAGNOSTICS 🩺

Most of the diagnostics are self explanatory, bestie. But if you are puzzled over the exact cause of failure, set the debugging level on (-D5) and run again 🔥. The debugging information will help you to pinpoint the exact cause of failure. periodt.

📜 HISTORY 📜

LPRng is a enhanced printer spooler system with functionality similar to the Berkeley LPR software 🌈. The LPRng mailing list is lprng@lprng.com — subscribe by sending mail to lprng-request@lprng.com with the word subscribe in the body 💖. The software is available from ftp://ftp.lprng.com/pub/LPRng. go off.

👑 AUTHOR 👑

Patrick Powell <papowell@lprng.com>.

and that's the whole page, babe — this manual is LPRng-3.9.0, and it's LPD.CONF(5), so if you see those two lil breadcrumbs at the bottom of the screen, that's just the source and version and date doin their thing 💅✨ 🦋

📦 where this page comes from