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<article>
  <articleinfo>
    <title>CUPS on FreeBSD</title>
    <pubdate>$FreeBSD$</pubdate>
    <authorgroup>
      <author>
	<firstname>Chess</firstname>
	<surname>Griffin</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>
  </sect1>

  <sect1 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
      <filename role="package">print/gutenprint-cups</filename> and
      <filename role="package">print/hplip</filename>, 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>
  </sect1>

  <sect1 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
      <groupname>cups</groupname> 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
add path 'usb/<replaceable>X</replaceable>.<replaceable>Y</replaceable>.<replaceable>Z</replaceable>' mode 0660 group cups</programlisting>

    <note>
      <para>Note that <replaceable>X</replaceable>,
	<replaceable>Y</replaceable>, and <replaceable>Z</replaceable>
	should be replaced with the target USB device listed in the
	<filename class="directory">/dev/usb</filename> directory that
	corresponds to the printer.  To find the correct device, examine
	the output of &man.dmesg.8;, where
	<filename>ugen<replaceable>X</replaceable>.<replaceable>Y</replaceable></filename>
	lists the printer device, which is a symbolic link to a USB
	device in <filename
	  class="directory">/dev/usb</filename>.</para>
    </note>

    <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 below should
      be uncommented in
      <filename>/usr/local/etc/cups/mime.types</filename> and
      <filename>/usr/local/etc/cups/mime.convs</filename>:</para>

    <programlisting>application/octet-stream</programlisting>

    <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>
  </sect1>

  <sect1 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 <ulink url="http://localhost:631"></ulink> 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> address for
      <hostid>localhost</hostid>.  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 <quote>Add
      Printer</quote> at the Administration screen of the
      <application>CUPS</application> web interface, or clicking one of
      the <quote>New Printers Found</quote> buttons also at the
      Administration screen.  When presented with the
      <quote>Device</quote> drop-down box, simply select the desired
      locally-attached printer, and then continue through the process.
      If one has added the <filename
      role="package">print/gutenprint-cups</filename> or <filename
      role="package">print/hplip</filename> 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>
  </sect1>

  <sect1 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>

    <sect2 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 <ulink url="http://localhost:631"></ulink> and
	click on <quote>Add Printer</quote> in the Administration
	section.  When presented with the <quote>Device</quote>
	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://<replaceable>server-name-or-ip</replaceable>/printers/<replaceable>printername</replaceable></programlisting>

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

      <para>In this case, <replaceable>server-ip</replaceable> would be
	replaced by the local <acronym>IP</acronym> address of the
	<application>CUPS</application> server on the network.</para>
    </sect2>

    <sect2 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://<replaceable>server-name-or-ip</replaceable>:631/printers/<replaceable>printername</replaceable></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>
    </sect2>
  </sect1>

  <sect1 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 file system.  It is also helpful to make
      sure your user is a member of the <groupname>cups</groupname>
      group.  If the permissions check boxes in the Administration
      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
      connects 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>
  </sect1>

  <sect1 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 <quote>knobs</quote> that one may want to
      add are:</para>

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

    <para>The first knob, <makevar>WITH_CUPS</makevar>, adds
      <application>CUPS</application> support to ports where applicable.
      The second knob, <makevar>CUPS_OVERWRITE_BASE</makevar>, 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
      <maketarget>buildworld</maketarget> system upgrade.  The third
      knob, <makevar>WITHOUT_LPR</makevar>, will prevent
      <application>LPR</application> support from being added to ports
      where applicable.</para>
  </sect1>
</article>

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