Linux man page for cups-lpd.8

cups-lpd(8) -- Linux man page

NAME

cups-lpd - receive print jobs and report printer status to lpd clients

SYNOPSIS

cups-lpd [ -o option=value ]

DESCRIPTION

cups-lpd is the CUPS Line Printer Daemon ("LPD") mini-server that supports legacy client systems that use the LPD protocol. cups-lpd does not act as a standalone network daemon but instead operates using the Internet "super-server" inetd(8). Add the following line to the inetd.conf file to enable the cups-lpd daemon:


    printer stream tcp nowait lp /path/to/cups/daemon/cups-lpd cups-lpd -o document-format=application/octet-stream

If you are using the newer xinetd(8) daemon, add the following lines to the xinetd.conf file:


    service printer
    {
        socket_type = stream
        protocol = tcp
        wait = no
        user = lp
        group = sys
        passenv =
        server = /path/to/cups/daemon/cups-lpd
        server_args = -o document-format=application/octet-stream
    }

The /path/to/cups/daemon is usually /usr/lib/cups/daemon or /usr/libexec/cups/daemon, depending on the operating system. Consult the cupsd.conf file for the local setting.

OPTIONS

The -o option to cups-lpd inserts options for all print queues. Most often this is used to disable the "l" filter so that remote print jobs are filtered as needed for printing:


    printer stream tcp nowait lp /usr/lib/cups/daemon/cups-lpd cups-lpd         -o document-format=application/octet-stream

    server = /usr/lib/cups/daemon/cups-lpd
    server_args = -o document-format=application/octet-stream

The example shown resets the document format to be application/octet-stream, which forces auto-detection of the print file type.

PERFORMANCE

cups-lpd performs well with small numbers of clients and printers. However, since a new process is created for each connection and since each process must query the printing system before each job submission, it does not scale to larger configurations. We highly recommend that large configurations use the native IPP support provided by CUPS instead.

SECURITY

cups-lpd currently does not perform any access control based on the settings in cupsd.conf(5) or in the hosts.allow(5) or hosts.deny files used by TCP wrappers. Therefore, running cups-lpd on your server will allow any computer on your network (and perhaps the entire Internet) to print to your server.

While xinetd has built-in access control support, you should use the TCP wrappers package with inetd to limit access to only those computers that should be able to print through your server.

cups-lpd is not enabled by the standard CUPS distribution. Please consult with your operating system vendor to determine whether it is enabled in their distributions.

COMPATIBILITY

cups-lpd does not enforce the restricted source port number specified in RFC 1179, as using restricted ports does not prevent users from submitting print jobs. While this behavior is different than standard Berkeley LPD implementations, it should not affect normal client operations.

The output of the status requests follows RFC 2569, Mapping between LPD and IPP Protocols. Since many LPD implementations stray from this definition, remote status reporting to LPD clients may be unreliable.