TCP/IP Printing

Line printer (LPR) is one of the network protocols and utilities of the TCP/IP protocol suite and is defined in RFC 1179. LPR provides a standard for transmitting TCP/IP print jobs between computers. With the LPR protocol, a client can send a print job to a print spooler service on another computer running the print spooler service known as line-printer daemon (LPD).

Windows NT provides both the LPR and LPD services for TCP/IP printing. In general, Windows NT supports TCP/IP printing as documented in RFC 1179. However, because RFC 1179 describes an existing print server protocol that is widely used on the Internet, but which is not an Internet standard, changes to printing under Windows NT 4.0 is somewhat different than printing described in RFC 1179. The following TCP/IP print enhancements were added to Windows NT version 4.0.

• Support for multiple data files per control file
• When used in "print through" mode as an intermediate spooler, the host name parameter is passed through the Windows printing subsystem
• LPR jobs are sourced from any reserved port between 512 and 1023

Note

Under Windows NT version 3.5x, all TCP/IP print jobs sent from a Windows NT computer were sourced from TCP ports 721 through 731, and, if many jobs were sent in quick succession, the ports could be "used up," causing a pause in printing until one of them passed through the TCP TIME_WAIT state.