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<article>
  <articleinfo>
    <title>CUPS on FreeBSD</title>
    <pubdate>$FreeBSD$</pubdate>
    <authorgroup>
      <author>
	<firstname>Chess</firstname>
	<surname>Grifin</surname>
	<affiliation>
	  <address><email>chess@chessgriffin.com</email></address>
	</affiliation>
      </author>
    </authorgroup>

    <legalnotice id="trademarks" role="trademarks">
      &tm-attrib.freebsd;
      &tm-attrib.general;
    </legalnotice>

    <abstract>
      <para>An article about configuring CUPS on &os;.</para>
    </abstract>
  </articleinfo>

  <sect1 id="printing-cups">
    <title>An Introduction to the Common Unix Printing System (CUPS)</title>

    <indexterm><primary>printing</primary></indexterm>
    <indexterm><primary>CUPS</primary></indexterm>

    <para><application>CUPS</application>, 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.</para>

    <para><application>CUPS</application> uses the Internet Printing
      Protocol (<acronym>IPP</acronym>) as the basis for managing
      print jobs and queues.  The Line Printer Daemon
      (<acronym>LPD</acronym>), Server Message Block
      (<acronym>SMB</acronym>), and AppSocket (a.k.a. JetDirect)
      protocols are also supported with reduced functionality.
      <application>CUPS</application> adds network printer browsing and
      PostScript Printer Description (<acronym>PPD</acronym>) based
      printing options to support real-world printing under &unix;.  As
      a result, <application>CUPS</application> is ideally-suited for
      sharing and accessing printers in mixed environments of &os;,
      &linux;, &macos;&nbsp;X, or &windows;.</para>

    <para>The main site for <application>CUPS</application> is <ulink
	url="http://www.cups.org/"></ulink>.</para>

    <sect2 id="printing-cups-install">
      <title>Installing the CUPS Print Server</title>

      <para><application>CUPS</application> can be installed from ports
	or by using a precompiled binary package.  To install
	<application>CUPS</application> from ports, issue the following
	command from a root terminal:</para>

      <screen>&prompt.root; <userinput>cd /usr/ports/print/cups && make install clean</userinput></screen>

      <para>To install <application>CUPS</application> using a
	precompiled binary, issue the following command from a root
	terminal:</para>

      <screen>&prompt.root; <userinput>pkg_add -r cups</userinput></screen>

      <para>Other optional, but recommended, ports or packages are
	<application>print/gutenprint-cups</application> and
	<application>print/hplip</application>, both of which add
	drivers and utilities for a variety of printers.  Once
	installed, the <application>CUPS</application> configuration
	files can be found in the directory
	<filename>/usr/local/etc/cups</filename>.</para>
    </sect2>

    <sect2 id="printing-cups-configuring-server">
      <title>Configuring the CUPS Print Server</title>

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

      <programlisting>[system=10]
add path 'unlpt*' mode 0660 group cups
add path 'ulpt*' mode 0660 group cups
add path 'lpt*' mode 0660 group cups</programlisting>

      <para>Next, add two lines to <filename>/etc/rc.conf</filename>
	as follows:</para>

      <programlisting>cupsd_enable="YES"
devfs_system_ruleset="system"</programlisting>

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

      <para>In order to enable <application>CUPS</application> printing
	under certain &microsoft.windows; clients, the line
	<programlisting>application/octet-stream</programlisting> should be
	uncommented in <filename>/usr/local/etc/cups/mime.types</filename>
	and <filename>/usr/local/etc/cups/mime.convs</filename>.</para>

      <para>Once these changes have been made, the &man.devfs.8; and
	<application>CUPS</application> systems must both be restarted,
	either by rebooting the computer or issuing the following two
	commands in a root terminal:</para>

      <screen>&prompt.root; <userinput>/etc/rc.d/devfs restart</userinput>
&prompt.root; <userinput>/usr/local/etc/rc.d/cupsd restart</userinput></screen>

    </sect2>

    <sect2 id="printing-cups-configuring-printers">
      <title>Configuring Printers on the CUPS Print Server</title>

      <para>After the <application>CUPS</application> system has been
	installed and configured, the administrator can begin configuring
	the local printers attached to the
	<application>CUPS</application> print server.  This part of the
	process is very similar, if not identical, to configuring
	<application>CUPS</application> printers on other &unix;-based
	operating systems, such as a &linux; distribution.</para>

      <para>The primary means for managing and administering the
	<application>CUPS</application> server is through the web-based
	interface, which can be found by launching a web browser and
	entering <filename>http://localhost:631</filename> in the
	browser's URL bar.  If the <application>CUPS</application>
	server is on another machine on the network, substitute the
	server's local <acronym>IP</acronym> addresss for
	<literal>localhost</literal>. The <application>CUPS</application>
	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 <application>CUPS</application>
	server, and whether to allow users additional access and
	privileges to the printers and print jobs.</para>

      <para>Adding a printer is generally as easy as clicking
	<literal>Add Printer</literal> at the Administration screen of
	the <application>CUPS</application> web interface, or clicking
	one of the <literal>New Printers Found</literal> buttons also
	at the Administration screen.  When presented with the
	<literal>Device</literal> drop-down box, simply select the
	desired locally-attached printer, and then continue through the
	process.  If one has added the
	<application>print/gutenprint-cups</application> or
	<application>print/hplip</application> ports or packages as
	referenced above, then additional print drivers will be available
	in the subsequent screens that might provide more stability or
	features.</para>
    </sect2>

    <sect2 id="printing-cups-clients">
      <title>Configuring CUPS Clients</title>

      <para>Once the <application>CUPS</application> 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
	<application>CUPS</application> 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.</para>

      <sect3 id="printing-cups-clients-unix">
	<title>&unix; Clients</title>

	<para><application>CUPS</application> will also need to be
	  installed on your &unix; clients.  Once
	  <application>CUPS</application> is installed on the clients,
	  then <application>CUPS</application> printers that are
	  shared across the network are often automatically discovered by
	  the printer managers for various desktop environments such as
	  <application>GNOME</application> or
	  <application>KDE</application>.  Alternatively, one can access
	  the local <application>CUPS</application> interface on the
	  client machine at <filename>http://localhost:631</filename> and
	  click on <literal>Add Printer</literal> in the Administration
	  section.  When presented with the <literal>Device</literal>
	  drop-down box, simply select the networked
	  <application>CUPS</application> printer, if it was
	  automatically discovered, or select <literal>ipp</literal> or
	  <literal>http</literal> and enter the <acronym>IPP</acronym> or
	  <acronym>HTTP</acronym> <acronym>URI</acronym> of the networked
	  <application>CUPS</application> printer, usually in one of the
	  two following syntaxes:</para>

	<programlisting>ipp://server-name-or-ip/printers/printername</programlisting>

	<programlisting>http://server-name-or-ip:631/printers/printername</programlisting>

	<para>If the <application>CUPS</application> clients have
	  difficulty finding other <application>CUPS</application>
	  printers shared across the network, sometimes it is helpful to
	  add or create a file
	  <filename>/usr/local/etc/cups/client.conf</filename> with a
	  single entry as follows:</para>

	<programlisting>ServerName (server-ip)</programlisting>

	<para>In this case, (server-ip) would be replaced by the local
	  <acronym>IP</acronym> address of the
	  <application>CUPS</application> server on the network.</para>
      </sect3>

      <sect3 id="printing-cups-clients-windows">
	<title>&windows; Clients</title>

	<para>Versions of &windows; prior to XP did not have the
	  capability to natively network with
	  <acronym>IPP</acronym>-based printers.  However, &windowsxp;
	  and later versions do have this capability.  Therefore, to
	  add a <application>CUPS</application> printer in these
	  versions of &windows; is quite easy.  Generally, the &windows;
	  administrator will run the &windows;
	  <literal>Add Printer</literal> wizard, select <literal>Network
	    Printer</literal> and then enter the <acronym>URI</acronym>
	  in the following syntax:</para>

	<programlisting>http://server-name-or-ip:631/printers/printername</programlisting>

	<para>If one has an older version of &windows; without native
	  <acronym>IPP</acronym> printing support, then the general
	  means of connecting to a <application>CUPS</application>
	  printer is to use
	  <filename role="package">net/samba3</filename> and
	  <application>CUPS</application> together, which is a topic
	  outside the scope of this chapter.</para>
      </sect3>
    </sect2>

    <sect2 id="printing-cups-troubleshooting">
      <title>CUPS Troubleshooting</title>

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

      <programlisting># Log general information in error_log - change "info" to "debug" for
# troubleshooting...
LogLevel info

# Administrator user group...
SystemGroup wheel

# Listen for connections on Port 631.
Port 631
#Listen localhost:631
Listen /var/run/cups.sock

# Show shared printers on the local network.
Browsing On
BrowseOrder allow,deny
#BrowseAllow @LOCAL
BrowseAllow 192.168.1.* # change to local LAN settings
BrowseAddress 192.168.1.* # change to local LAN settings

# Default authentication type, when authentication is required...
DefaultAuthType Basic
DefaultEncryption Never # comment this line to allow encryption

# Allow access to the server from any machine on the LAN
&lt;Location /&gt;
  Order allow,deny
  #Allow localhost
  Allow 192.168.1.* # change to local LAN settings
&lt;/Location&gt;

# Allow access to the admin pages from any machine on the LAN
&lt;Location /admin&gt;
  #Encryption Required
  Order allow,deny
  #Allow localhost
  Allow 192.168.1.* # change to local LAN settings
&lt;/Location&gt;

# Allow access to configuration files from any machine on the LAN
&lt;Location /admin/conf&gt;
  AuthType Basic
  Require user @SYSTEM
  Order allow,deny
  #Allow localhost
  Allow 192.168.1.* # change to local LAN settings
&lt;/Location&gt;

# Set the default printer/job policies...
&lt;Policy default&gt;
  # Job-related operations must be done by the owner or an adminstrator...
  &lt;Limit Send-Document Send-URI Hold-Job Release-Job Restart-Job Purge-Jobs \
Set-Job-Attributes Create-Job-Subscription Renew-Subscription Cancel-Subscription \
Get-Notifications Reprocess-Job Cancel-Current-Job Suspend-Current-Job Resume-Job \
CUPS-Move-Job&gt;
    Require user @OWNER @SYSTEM
    Order deny,allow
  &lt;/Limit&gt;

  # All administration operations require an adminstrator to authenticate...
  &lt;Limit Pause-Printer Resume-Printer Set-Printer-Attributes Enable-Printer \
Disable-Printer Pause-Printer-After-Current-Job Hold-New-Jobs Release-Held-New-Jobs \
Deactivate-Printer Activate-Printer Restart-Printer Shutdown-Printer Startup-Printer \
Promote-Job Schedule-Job-After CUPS-Add-Printer CUPS-Delete-Printer CUPS-Add-Class \
CUPS-Delete-Class CUPS-Accept-Jobs CUPS-Reject-Jobs CUPS-Set-Default&gt;
    AuthType Basic
    Require user @SYSTEM
    Order deny,allow
  &lt;/Limit&gt;

  # Only the owner or an administrator can cancel or authenticate a job...
  &lt;Limit Cancel-Job CUPS-Authenticate-Job&gt;
    Require user @OWNER @SYSTEM
    Order deny,allow
  &lt;/Limit&gt;

  &lt;Limit All&gt;
    Order deny,allow
  &lt;/Limit&gt;
&lt;/Policy&gt;</programlisting>
    </sect2>

    <sect2 id="printing-cups-ports-knobs">
      <title>Fine Tuning CUPS-Related Ports</title>

      <para>If <application>CUPS</application> is going to serve as the
	primary printing system, then one may choose to optionally add
	certain knobs to <filename>/etc/make.conf</filename> that will
	emphasize <application>CUPS</application> over other printing
	options.  Some of these "knobs" that one may want to add
	are:</para>

      <programlisting>WITH_CUPS=YES
CUPS_OVERWRITE_BASE=YES
WITHOUT_LPR=YES</programlisting>

      <para>The first knob, WITH_CUPS, adds
	<application>CUPS</application> support to ports where
	applicable.  The second knob, CUPS_OVERWRITE_BASE, will fix
	certain symlinks and paths that would otherwise apply to the
	default &os; printing system, <application>LPR</application>,
	and will prevent these fixes from being reverted upon the next
	"buildworld" system upgrade.  The third knob, WITHOUT_LPR, will
	prevent <application>LPR</application> support from being added
	to ports where applicable.</para>
    </sect2>
  </sect1>
</article>

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