Line Printer Daemon, also known as the Berkeley printing system, is commonly referred to as LPD. Line Printer Daemon is a printer protocol using TCPIP to connect between a printer and a workstation on a network, LAN, or WAN. UNIX was the original target for LPD usage and there are many types of LPD software for UNIX printing available today.
An LPD printer may be an IP address of the PC on the network, or it could be a device, in addition to the queue name. Each queue has it’s own settings with instructions of where to send and what to do with the file. LPD software is usually installed on the PC receiving the print files from the host system. Or, the LPD software can be installed on a print server that has a list of the network printers it may print to.
Line Printer Daemon and an LPR
An LPR (Line Printer Request) typically sends the print request or print file to the address (IP) of the Line Printer Daemon, whether on a PC or Server. If you have a robust and high-end print server (LPD) installed, you can convert to PDF, email the print file, or print the file to one of the printers that the LPD can see within the network.
An LPD will listen for messages on the TCP port 515 from various programs such as LPR, LPRM, LPQ, LPC programs. LPD isn’t limited to local messages, it can also listen to network messages from a remote client using the LPD protocol.
Line Printer Daemon Software
RPM Remote Print Manager is one of the best line printer daemons on the market. RPM installs on Windows and receives print files from ANY host system (mainframe, midrange, UNIX, Linux, and Windows®) via TCPIP and print them to your Windows printer (networked, local or shared). RPM has many features that a standard LPD or print server do not offer. RPM can take a print job and save it to disk for archiving or processing, email it, convert the print job into PDF or HTML and more.