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Line printer daemon protocol (RFC1179)

IP.com Disclosure Number: IPCOM000001992D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 11 page(s) / 22K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

L. McLaughlin: AUTHOR



This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 12% of the total text.

Network Printing Working Group L. McLaughlin III, Editor

Request for Comments: 1179 The Wollongong Group

August 1990

Line Printer Daemon Protocol

Status of this Memo

This RFC describes an existing print server protocol widely used on

the Internet for communicating between line printer daemons (both

clients and servers). This memo is for informational purposes only,

and does not specify an Internet standard. Please refer to the

current edition of the "IAB Official Protocol Standards" for the

standardization state and status of this protocol. Distribution of

this memo is unlimited.

1. Introduction

The Berkeley versions of the Unix(tm) operating system provide line

printer spooling with a collection of programs: lpr (assign to

queue), lpq (display the queue), lprm (remove from queue), and lpc

(control the queue). These programs interact with an autonomous

process called the line printer daemon. This RFC describes the

protocols with which a line printer daemon client may control


This memo is based almost entirely on the work of Robert Knight at

Princeton University. I gratefully acknowledge his efforts in

deciphering the UNIX lpr protocol and producing earlier versions of

this document.

2. Model of Printing Environment

A group of hosts request services from a line printer daemon process

running on a host. The services provided by the process are related

to printing jobs. A printing job produces output from one file.

Each job will have a unique job number which is between 0 and 999,

inclusive. The jobs are requested by users which have names. These

user names may not start with a digit.

3. Specification of the Protocol

The specification includes file formats for the control and data

files as well as messages used by the protocol.

3.1 Message formats

LPR is a a TCP-based protocol. The port on which a line printer

daemon listens is 515. The source port must be in the range 721 to

731, inclusive. A line printer daemon responds to commands send to

its port. All commands begin with a single octet code, which is a

binary number which represents the requested function. The code is

immediately followed by the ASCII name of the printer queue name on

which the function is to be performed. If there are other operands

to the command, they are separated from the printer queue name with

white space (ASCII space, horizontal tab, vertical tab, and form

feed). The end of the command is indicated with an ASCII line f...