Historically, Linux systems have used the BSD LPD printing system, but this system is showing its age. Various alternatives exist to this system, and Linux distributions are increasingly using them ”usually LPRng or CUPS. These alternatives offer improved access control mechanisms and other features. CUPS, in particular, offers an improved ability to interact with printing applications in order to convey printer-specific features to the applications, and a Web-based configuration tool for print client configuration.
Security should be a concern on any computer that functions as a print server. Ideally, you should use packet filter firewall rules to block access to ports 515 and 631 (the LPD and IPP printing ports, respectively) to any but authorized hosts , and use access control features specific to each printing tool as a redundant measure. LPRng offers the best control over LPD printing mechanisms, while CUPS offers good control over IPP tools.