CUPS on FreeBSD

CUPS, the Common UNIX Printing System, provides a portable printing layer for UNIX®-based operating systems. It has been developed by Easy Software Products to promote a standard printing solution for all UNIX® vendors and users.

CUPS uses the Internet Printing Protocol (IPP) as the basis for managing print jobs and queues. The Line Printer Daemon (LPD), Server Message Block (SMB), and AppSocket (aka JetDirect) protocols are also supported with reduced functionality. CUPS adds network printer browsing and PostScript Printer Description (PPD) based printing options to support real-world printing under UNIX®. As a result, CUPS is ideally-suited for sharing and accessing printers in mixed environments of FreeBSD, Linux®, Mac OS® X, or Windows®.

The main site for CUPS is http://www.cups.org/.

To install CUPS using a precompiled binary, issue the following command from a root terminal:

Other optional, but recommended, packages are print/gutenprint and print/hplip, both of which add drivers and utilities for a variety of printers. Once installed, the CUPS configuration files can be found in the directory /usr/local/etc/cups.

After installation, a few files must be edited to configure the CUPS server. First, create or modify, as the case may be, the file /etc/devfs.rules and add the following information to set the proper permissions on all potential printer devices and to associate printers with the cups user group:

Next, add two lines to /etc/rc.conf as follows:

These two entries will start the CUPS print server on boot and invoke the local devfs rule created above, respectively.

To enable CUPS printing under certain Microsoft® Windows® clients, the line below should be uncommented in /usr/local/etc/cups/mime.types and /usr/local/etc/cups/mime.convs:

Once these changes have been made, the devfs(8) and CUPS systems must both be restarted, either by rebooting the computer or issuing the following two commands in a root terminal:

After the CUPS system has been installed and configured, the administrator can begin configuring the local printers attached to the CUPS print server. This part of the process is very similar, if not identical, to configuring CUPS printers on other UNIX®-based operating systems, such as a Linux® distribution.

The primary means for managing and administering the CUPS server is through the web-based interface, which can be found by launching a web browser and entering http://localhost:631 in the browser’s URL bar. If the CUPS server is on another machine on the network, substitute the server’s local IP address for localhost. The CUPS web interface is fairly self-explanatory, as there are sections for managing printers and print jobs, authorizing users, and more. Additionally, on the right-hand side of the Administration screen are several check-boxes allowing easy access to commonly-changed settings, such as whether to share published printers connected to the system, whether to allow remote administration of the CUPS server, and whether to allow users additional access and privileges to the printers and print jobs.

Adding a printer is generally as easy as clicking "Add Printer" at the Administration screen of the CUPS web interface, or clicking one of the "New Printers Found" buttons also at the Administration screen. When presented with the "Device" drop-down box, simply select the desired locally-attached printer, and then continue through the process. If one has added the print/gutenprint-cups or print/hplip ports or packages as referenced above, then additional print drivers will be available in the subsequent screens that might provide more stability or features.

Once the CUPS server has been configured and printers have been added and published to the network, the next step is to configure the clients, or the machines that are going to access the CUPS server. If one has a single desktop machine that is acting as both server and client, then much of this information may not be needed.

Difficulties with CUPS often lies in permissions. First, double check the devfs(8) permissions as outlined above. Next, check the actual permissions of the devices created in the file system. It is also helpful to make sure your user is a member of the cups group. If the permissions check boxes in the Administration section of the CUPS web interface do not seem to be working, another fix might be to manually backup the main CUPS configuration file located at /usr/local/etc/cups/cupsd.conf and edit the various configuration options and try different combinations of configuration options. One sample /usr/local/etc/cups/cupsd.conf to test is listed below. Please note that this sample cupsd.conf sacrifices security for easier configuration; once the administrator successfully connects to the CUPS server and configures the clients, it is advisable to revisit this configuration file and begin locking down access.