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<!--
     The FreeBSD Documentation Project

     $FreeBSD$
-->

<chapter id="mail">
  <chapterinfo>
    <authorgroup>
      <author>
	<firstname>Bill</firstname>
	<surname>Lloyd</surname>
	<contrib>Original work by </contrib>
      </author>
    </authorgroup>
    <authorgroup>
      <author>
	<firstname>Jim</firstname>
	<surname>Mock</surname>
	<contrib>Rewritten by </contrib>
	<!-- 2 Dec 1999 -->
      </author>
    </authorgroup>
  </chapterinfo>

  <title>Electronic Mail</title>

  <sect1 id="mail-synopsis">
    <title>Synopsis</title>
    <indexterm><primary>email</primary></indexterm>

    <para><quote>Electronic Mail</quote>, better known as email, is one of the
      most widely used forms of communication today.  This chapter provides
      a basic introduction to running a mail server on &os;, as well as an
      introduction to sending and receiving email using &os;; however,
      it is not a complete reference and in fact many important
      considerations are omitted.  For more complete coverage of the
      subject, the reader is referred to the many excellent books listed
      in <xref linkend="bibliography">.</para>

    <para>After reading this chapter, you will know:</para>

    <itemizedlist>
      <listitem>
	<para>What software components are involved in sending and receiving
	  electronic mail.</para>
      </listitem>

      <listitem>
	<para>Where basic <application>sendmail</application> configuration
	  files are located in FreeBSD.</para>
      </listitem>

      <listitem>
        <para>The difference between remote and
	  local mailboxes.</para>
      </listitem>

      <listitem>
	<para>How to block spammers from illegally using your mail server as a
	  relay.</para>
      </listitem>

      <listitem>
	<para>How to install and configure an alternate Mail Transfer Agent on
	  your system, replacing <application>sendmail</application>.</para>
      </listitem>

      <listitem>
	<para>How to troubleshoot common mail server problems.</para>
      </listitem>

      <listitem>
	<para>How to use SMTP with UUCP.</para>
      </listitem>

      <listitem>
	<para>How to set up the system to send mail only.</para>
      </listitem>

      <listitem>
	<para>How to use mail with a dialup connection.</para>
      </listitem>

      <listitem>
        <para>How to configure SMTP Authentication for added security.</para>
      </listitem>

      <listitem>
        <para>How to install and use a Mail User Agent, such as
	  <application>mutt</application> to send and receive email.</para>
      </listitem>

      <listitem>

        <para>How to download your mail from a remote <acronym>POP</acronym>
	  or <acronym>IMAP</acronym> server.</para>
      </listitem>

      <listitem>
        <para>How to automatically apply filters and rules to incoming
	  email.</para>
      </listitem>
    </itemizedlist>

    <para>Before reading this chapter, you should:</para>

    <itemizedlist>
      <listitem>
	<para>Properly set up your network connection
	  (<xref linkend="advanced-networking">).</para>
      </listitem>

      <listitem>
	<para>Properly set up the DNS information for your mail host
	  (<xref linkend="network-servers">).</para>
      </listitem>

      <listitem>
	<para>Know how to install additional third-party software
	  (<xref linkend="ports">).</para></listitem>
    </itemizedlist>
  </sect1>

  <sect1 id="mail-using">
    <title>Using Electronic Mail</title>
    <indexterm><primary>POP</primary></indexterm>
    <indexterm><primary>IMAP</primary></indexterm>
    <indexterm><primary>DNS</primary></indexterm>

    <para>There are five major parts involved in an email exchange.  They
      are: <link linkend="mail-mua">the user program</link>, <link
      linkend="mail-mta">the server daemon</link>, <link
      linkend="mail-dns">DNS</link>, <link linkend="mail-receive">a
      remote or local mailbox</link>, and of course, <link linkend="mail-host">the
      mailhost itself</link>.</para>

    <sect2 id="mail-mua">
      <title>The User Program</title>

      <para>This includes command line programs such as
	<application>mutt</application>,
	<application>alpine</application>, <application>elm</application>,
	and <command>mail</command>, and <acronym>GUI</acronym> programs such as
	<application>balsa</application>,
	<application>xfmail</application> to name a few, and something
	more <quote>sophisticated</quote> like a WWW browser.  These
	programs simply pass off the email transactions to the local
	<link linkend="mail-host"><quote>mailhost</quote></link>, either
	by calling one of the <link linkend="mail-mta">server
	daemons</link> available, or delivering it over <acronym>TCP</acronym>.</para>
	</sect2>

    <sect2 id="mail-mta">
      <title>Mailhost Server Daemon</title>
      <indexterm>
        <primary>mail server daemons</primary>
        <secondary><application>sendmail</application></secondary>
      </indexterm>
      <indexterm>
        <primary>mail server daemons</primary>
        <secondary><application>postfix</application></secondary>
      </indexterm>
      <indexterm>
        <primary>mail server daemons</primary>
        <secondary><application>qmail</application></secondary>
      </indexterm>
      <indexterm>
        <primary>mail server daemons</primary>
        <secondary><application>exim</application></secondary>
      </indexterm>

      <para>&os; ships with <application>sendmail</application> by
	default, but also support numerous other mail server daemons,
	just some of which include:</para>

      <itemizedlist>
	<listitem>
	  <para><application>exim</application>;</para>
	</listitem>

	<listitem>
	  <para><application>postfix</application>;</para>
	</listitem>

	<listitem>
	  <para><application>qmail</application>.</para>
	</listitem>
      </itemizedlist>

      <para>The server daemon usually has two functions&mdash;it is responsible
	for receiving incoming mail as well as delivering outgoing mail.  It is
	<emphasis>not</emphasis> responsible for the collection of mail using protocols
	such as <acronym>POP</acronym> or <acronym>IMAP</acronym> to
	read your email, nor does it allow connecting to local
	<filename>mbox</filename> or Maildir mailboxes.  You may require
	an additional <link linkend="mail-receive">daemon</link> for
	that.</para>

      <warning>
	<para>Older versions of <application>sendmail</application>
	  have some serious security issues which may result in an
	  attacker gaining local and/or remote access to your machine.
	  Make sure that you are running a current version to avoid
	  these problems.  Optionally, install an alternative
	  <acronym>MTA</acronym> from the <link linkend="ports">&os;
	  Ports Collection</link>.</para>
      </warning>
    </sect2>

    <sect2 id="mail-dns">
      <title>Email and DNS</title>

      <para>The Domain Name System (DNS) and its daemon
        <command>named</command> play a large role in the delivery of
	email.  In order to deliver mail from your site to another, the
	server daemon will look up the remote site in the DNS to determine the
	host that will receive mail for the destination.  This process
	also occurs when mail is sent from a remote host to your mail
	server.</para>

      <indexterm>
	<primary>MX record</primary>
      </indexterm>

      <para><acronym>DNS</acronym> is responsible for mapping
	hostnames to IP addresses, as well as for storing information
	specific to mail delivery, known as MX records.  The MX (Mail
	eXchanger) record specifies which host, or hosts, will receive
	mail for a particular domain.  If you do not have an MX record
	for your hostname or domain, the mail will be delivered
	directly to your host provided you have an A record pointing
	your hostname to your IP address.</para>

      <para>You may view the MX records for any domain by using the
	&man.host.1; command, as seen in the example below:</para>

      <screen>&prompt.user; <userinput>host -t mx FreeBSD.org</userinput>
FreeBSD.org mail is handled (pri=10) by mx1.FreeBSD.org</screen>
    </sect2>

    <sect2 id="mail-receive">
      <title>Receiving Mail</title>
      <indexterm>
        <primary>email</primary>
        <secondary>receiving</secondary>
      </indexterm>

      <para>Receiving mail for your domain is done by the mail host.  It
	will collect all mail sent to your domain and store it
	either in <filename>mbox</filename> (the default method for storing mail) or Maildir format, depending
	on your configuration.
	Once mail has been stored, it may either be read locally using
	applications such as &man.mail.1; or
	<application>mutt</application>, or remotely accessed and
	collected using protocols such as 
	<acronym>POP</acronym> or <acronym>IMAP</acronym>.
	This means that should you only
	wish to read mail locally, you are not required to install a
	<acronym>POP</acronym> or <acronym>IMAP</acronym> server.</para>

      <sect3 id="pop-and-imap">
        <title>Accessing remote mailboxes using <acronym>POP</acronym> and <acronym>IMAP</acronym></title>

        <indexterm><primary>POP</primary></indexterm>
        <indexterm><primary>IMAP</primary></indexterm>
	<para>In order to access mailboxes remotely, you are required to
	  have access to a <acronym>POP</acronym> or <acronym>IMAP</acronym>
	  server.  These protocols allow users to connect to their mailboxes from
	  remote locations with ease.  Though both
	  <acronym>POP</acronym> and <acronym>IMAP</acronym> allow users
	  to remotely access mailboxes, <acronym>IMAP</acronym> offers
	  many advantages, some of which are:</para>

        <itemizedlist>
          <listitem>
	    <para><acronym>IMAP</acronym> can store messages on a remote
	      server as well as fetch them.</para>
          </listitem>

          <listitem>
	    <para><acronym>IMAP</acronym> supports concurrent updates.</para>
          </listitem>

          <listitem>
	    <para><acronym>IMAP</acronym> can be extremely useful over
	      low-speed links as it allows users to fetch the structure
	      of messages without downloading them; it can also
	      perform tasks such as searching on the server in
	      order to minimize data transfer between clients and
	      servers.</para>
          </listitem>

        </itemizedlist>

        <para>In order to install a <acronym>POP</acronym> or
	  <acronym>IMAP</acronym> server, the following steps should be
	  performed:</para>

        <procedure>
	  <step>
	    <para>Choose an <acronym>IMAP</acronym> or
	      <acronym>POP</acronym> server that best suits your needs.
	      The following <acronym>POP</acronym> and
	      <acronym>IMAP</acronym> servers are well known and serve
	      as some good examples:</para>

	      <itemizedlist>
	        <listitem>
		  <para><application>qpopper</application>;</para>
	        </listitem>

	        <listitem>
		  <para><application>teapop</application>;</para>
	        </listitem>

	        <listitem>
		  <para><application>imap-uw</application>;</para>
	        </listitem>

	        <listitem>
		  <para><application>courier-imap</application>;</para>
	        </listitem>
	        
                <listitem>
		  <para><application>dovecot</application>;</para>
	        </listitem>
	      </itemizedlist>

	  </step>

          <step>
	    <para>Install the <acronym>POP</acronym> or
	      <acronym>IMAP</acronym> daemon of your choosing from the
	      ports
	      collection.</para>
	  </step>

	  <step>
	    <para>Where required, modify <filename>/etc/inetd.conf</filename>
	      to load the <acronym>POP</acronym> or
	      <acronym>IMAP</acronym> server.</para>
	  </step>
        </procedure>

	<warning>
	  <para>It should be noted that both <acronym>POP</acronym> and
	    <acronym>IMAP</acronym> transmit information, including
	    username and password credentials in clear-text.  This means
	    that if you wish to secure the transmission of information
	    across these protocols, you should consider tunneling
	    sessions over &man.ssh.1; or using SSL.  Tunneling sessions is
	    described in <xref linkend="security-ssh-tunneling"> and SSL is
	    described in <xref linkend="openssl">.</para>
        </warning>
      </sect3>

      <sect3 id="local">
        <title>Accessing local mailboxes</title>

	<para>Mailboxes may be accessed locally by directly utilizing
	  <acronym>MUA</acronym>s on the server on which the mailbox
	  resides.  This can be done using applications such as
	  <application>mutt</application> or &man.mail.1;.
	</para>
      </sect3>
    </sect2>

    <sect2 id="mail-host">
      <title>The Mail Host</title>
      <indexterm><primary>mail host</primary></indexterm>

      <para>The mail host is the name given to a server that is
        responsible for delivering and receiving mail for your host, and
	possibly your network.</para>
    </sect2>
  </sect1>

  <sect1 id="sendmail">
    <sect1info>
      <authorgroup>
        <author>
          <firstname>Christopher</firstname>
          <surname>Shumway</surname>
          <contrib>Contributed by </contrib>
        </author>
      </authorgroup>
    </sect1info>
    <title><application>sendmail</application> Configuration</title>

    <indexterm>
      <primary><application>sendmail</application></primary>
    </indexterm>

    <para>&man.sendmail.8; is the default Mail Transfer Agent (MTA) in
      FreeBSD.  <application>sendmail</application>'s job is to accept
      mail from Mail User Agents (<acronym>MUA</acronym>) and deliver it
      to the appropriate mailer as defined by its configuration file.
      <application>sendmail</application> can also accept network
      connections and deliver mail to local mailboxes or deliver it to
      another program.</para>

    <para><application>sendmail</application> uses the following
      configuration files:</para>

    <indexterm>
      <primary><filename>/etc/mail/access</filename></primary>
    </indexterm>
    <indexterm>
      <primary><filename>/etc/mail/aliases</filename></primary>
    </indexterm>
    <indexterm>
      <primary><filename>/etc/mail/local-host-names</filename></primary>
    </indexterm>
    <indexterm>
      <primary><filename>/etc/mail/mailer.conf</filename></primary>
    </indexterm>
    <indexterm>
      <primary><filename>/etc/mail/mailertable</filename></primary>
    </indexterm>
    <indexterm>
      <primary><filename>/etc/mail/sendmail.cf</filename></primary>
    </indexterm>
    <indexterm>
      <primary><filename>/etc/mail/virtusertable</filename></primary>
    </indexterm>
    <informaltable frame="none" pgwide="1">
      <tgroup cols="2">
	<thead>
	  <row>
	    <entry>Filename</entry>
	    <entry>Function</entry>
	  </row>
	</thead>
	<tbody>
	  <row>
	    <entry>
	      <filename>/etc/mail/access</filename>
	    </entry>
	    <entry><application>sendmail</application> access database
 	      file</entry>
	  </row>
	  <row>
	    <entry>
	      <filename>/etc/mail/aliases</filename>
	    </entry>
	    <entry>Mailbox aliases</entry>
	  </row>
	  <row>
	    <entry>
	      <filename>/etc/mail/local-host-names</filename>
	    </entry>
	    <entry>Lists of hosts <application>sendmail</application>
	    accepts mail for</entry>
    </row>
	  <row>
	    <entry>
	      <filename>/etc/mail/mailer.conf</filename>
	    </entry>
	    <entry>Mailer program configuration</entry>
	  </row>
	  <row>
	    <entry>
	      <filename>/etc/mail/mailertable</filename>
	    </entry>
	    <entry>Mailer delivery table</entry>
	  </row>
	  <row>
	    <entry>
	      <filename>/etc/mail/sendmail.cf</filename>
	    </entry>
	    <entry><application>sendmail</application> master
	    configuration file</entry>
	  </row>
	  <row>
	    <entry>
	      <filename>/etc/mail/virtusertable</filename>
	    </entry>
	    <entry>Virtual users and domain tables</entry>
	  </row>
	</tbody>
      </tgroup>
    </informaltable>

  <sect2>
    <title><filename>/etc/mail/access</filename></title>

    <para>The access database defines what host(s) or IP addresses
      have access to the local mail server and what kind of access
      they have.  Hosts can be listed as <option>OK</option>,
      <option>REJECT</option>, <option>RELAY</option> or simply passed
      to <application>sendmail</application>'s error handling routine with a given mailer error.
      Hosts that are listed as <option>OK</option>, which is the
      default, are allowed to send mail to this host as long as the
      mail's final destination is the local machine.  Hosts that are
      listed as <option>REJECT</option> are rejected for all mail
      connections.  Hosts that have the <option>RELAY</option> option
      for their hostname are allowed to send mail for any destination
      through this mail server.</para>

      <example>
	<title>Configuring the <application>sendmail</application>
  	  Access Database</title>

    <programlisting>cyberspammer.com                550 We do not accept mail from spammers
FREE.STEALTH.MAILER@            550 We do not accept mail from spammers
another.source.of.spam          REJECT
okay.cyberspammer.com           OK
128.32                          RELAY</programlisting>
      </example>

   <para>In this example we have five entries.  Mail senders that
     match the left hand side of the table are affected by the action
     on the right side of the table.  The first two examples give an
     error code to <application>sendmail</application>'s error
     handling routine.  The message is printed to the remote host when
     a mail matches the left hand side of the table.  The next entry
     rejects mail from a specific host on the Internet,
     <hostid>another.source.of.spam</hostid>.  The next entry accepts
     mail connections from a host
     <hostid role="fqdn">okay.cyberspammer.com</hostid>, which is more exact than
     the <hostid role="domainname">cyberspammer.com</hostid> line above.  More specific
     matches override less exact matches.  The last entry allows
     relaying of electronic mail from hosts with an IP address that
     begins with <hostid>128.32</hostid>.  These hosts would be able
     to send mail through this mail server that are destined for other
     mail servers.</para>

   <para>When this file is updated, you need to run
     <command>make</command> in <filename>/etc/mail/</filename> to
     update the database.</para>

   </sect2>
   <sect2>
    <title><filename>/etc/mail/aliases</filename></title>

    <para>The aliases database contains a list of virtual mailboxes
      that are expanded to other user(s), files, programs or other
      aliases.  Here are a few examples that can be used in
      <filename>/etc/mail/aliases</filename>:</para>

      <example>
	<title>Mail Aliases</title>
    <programlisting>root: localuser
ftp-bugs: joe,eric,paul
bit.bucket:  /dev/null
procmail: "|/usr/local/bin/procmail"</programlisting>
      </example>

      <para>The file format is simple; the mailbox name on the left
	side of	the colon is expanded to the target(s) on the right.
	The
	first example simply expands the mailbox <username>root</username>
	to the mailbox <username>localuser</username>, which is then
	looked up again in the aliases database.  If no match is found,
	then the message is delivered to the local user
	<username>localuser</username>.  The next example shows a mail
	list.  Mail to the mailbox <username>ftp-bugs</username> is
	expanded to the three local mailboxes <username>joe</username>,
	<username>eric</username>, and <username>paul</username>.  Note
	that a remote mailbox could be specified as <email>user@example.com</email>.  The
	next example shows writing mail to a file, in this case
	<filename>/dev/null</filename>.  The last example shows sending
	mail to a program, in this case the mail message is written to the
	standard input of <filename>/usr/local/bin/procmail</filename>
	through a &unix; pipe.</para>

   <para>When this file is updated, you need to run
   <command>make</command> in <filename>/etc/mail/</filename> to
   update the database.</para>
  </sect2>
  <sect2>
    <title><filename>/etc/mail/local-host-names</filename></title>

    <para>This is a list of hostnames &man.sendmail.8; is to accept as
      the local host name.  Place any domains or hosts that
      <application>sendmail</application> is to be receiving mail for.
      For example, if this mail server was to accept mail for the
      domain <hostid role="domainname">example.com</hostid> and the host
      <hostid role="fqdn">mail.example.com</hostid>, its
      <filename>local-host-names</filename> might look something like
      this:</para>

    <programlisting>example.com
mail.example.com</programlisting>

    <para>When this file is updated, &man.sendmail.8; needs to be
    restarted to read the changes.</para>

  </sect2>

  <sect2>
    <title><filename>/etc/mail/sendmail.cf</filename></title>

    <para><application>sendmail</application>'s master configuration
      file, <filename>sendmail.cf</filename> controls the overall
      behavior of <application>sendmail</application>, including everything
      from rewriting e-mail addresses to printing rejection messages to
      remote mail servers.  Naturally, with such a diverse role, this
      configuration file is quite complex and its details are a bit
      out of the scope of this section.  Fortunately, this file rarely
      needs to be changed for standard mail servers.</para>

    <para>The master <application>sendmail</application> configuration
      file can be built from &man.m4.1; macros that define the features
      and behavior of <application>sendmail</application>.  Please see
      <filename>/usr/src/contrib/sendmail/cf/README</filename> for
      some of the details.</para>

    <para>When changes to this file are made,
      <application>sendmail</application> needs to be restarted for
      the changes to take effect.</para>

  </sect2>
  <sect2>
    <title><filename>/etc/mail/virtusertable</filename></title>

    <para>The <filename>virtusertable</filename> maps mail addresses for
      virtual domains and
      mailboxes to real mailboxes.  These mailboxes can be local,
      remote, aliases defined in
      <filename>/etc/mail/aliases</filename> or files.</para>

    <example>
	<title>Example Virtual Domain Mail Map</title>

    <programlisting>root@example.com                root
postmaster@example.com          postmaster@noc.example.net
@example.com                    joe</programlisting>
      </example>

    <para>In the above example, we have a mapping for a domain
      <hostid role="domainname">example.com</hostid>.  This file is processed in a
      first match order down the file.  The first item maps
      <email>root@example.com</email> to the local mailbox <username>root</username>.  The next entry maps
      <email>postmaster@example.com</email> to the mailbox <username>postmaster</username> on the host
      <hostid role="fqdn">noc.example.net</hostid>.  Finally, if nothing from <hostid role="domainname">example.com</hostid> has
      matched so far, it will match the last mapping, which matches
      every other mail message addressed to someone at
      <hostid role="domainname">example.com</hostid>.
      This will be mapped to the local mailbox <username>joe</username>.</para>

  </sect2>
  </sect1>

  <sect1 id="mail-changingmta">
    <sect1info>
      <authorgroup>
        <author>
          <firstname>Andrew</firstname>
          <surname>Boothman</surname>
          <contrib>Written by </contrib>
        </author>
      </authorgroup>
      <authorgroup>
        <author>
          <firstname>Gregory</firstname>
          <surname>Neil Shapiro</surname>
          <contrib>Information taken from e-mails written by </contrib>
        </author>
      </authorgroup>
    </sect1info>
    <title>Changing Your Mail Transfer Agent</title>
    <indexterm>
      <primary>email</primary>
      <secondary>change mta</secondary>
    </indexterm>

    <para>As already mentioned, FreeBSD comes with
      <application>sendmail</application> already installed as your
      MTA (Mail Transfer Agent).  Therefore by default it is
      in charge of your outgoing and incoming mail.</para>

    <para>However, for a variety of reasons, some system
      administrators want to change their system's MTA.  These
      reasons range from simply wanting to try out another MTA to
      needing a specific feature or package which relies on another
      mailer.  Fortunately, whatever the reason, FreeBSD makes it
      easy to make the change.</para>

    <sect2>
      <title>Install a New MTA</title>

      <para>You have a wide choice of MTAs available.  A good
	starting point is the
	<link linkend="ports">FreeBSD Ports Collection</link> where
	you will be able to find many.  Of course you are free to use
	any MTA you want from any location, as long as you can make
	it run under FreeBSD.</para>

      <para>Start by installing your new MTA.  Once it is installed
	it gives you a chance to decide if it really fulfills your
	needs, and also gives you the opportunity to configure your
	new software before getting it to take over from
	<application>sendmail</application>.  When doing this, you
	should be sure that installing the new software will not attempt
	to overwrite system binaries such as
	<filename>/usr/bin/sendmail</filename>.  Otherwise, your new
	mail software has essentially been put into service before
	you have configured it.</para>

      <para>Please refer to your chosen MTA's documentation for
	information on how to configure the software you have
	chosen.</para>
    </sect2>

    <sect2 id="mail-disable-sendmail">
      <title>Disable <application>sendmail</application></title>

	<warning>
	  <para>If you disable <application>sendmail</application>'s
	    outgoing mail service, it is important that you replace it
	    with an alternative mail delivery system.  If
	    you choose not to, system functions such as &man.periodic.8;
	    will be unable to deliver their results by e-mail as they
	    would normally expect to.  Many parts of your system may
	    expect to have a functional
	    <application>sendmail</application>-compatible system.  If
	    applications continue to use
	    <application>sendmail</application>'s binaries to try to send
	    e-mail after you have disabled them, mail could go into an
	    inactive <application>sendmail</application> queue, and
	    never be delivered.</para>
	</warning>

	<para>In order to completely disable
	  <application>sendmail</application>, including the outgoing
	  mail service, you must use</para>

	  <programlisting>sendmail_enable="NO"
sendmail_submit_enable="NO"
sendmail_outbound_enable="NO"
sendmail_msp_queue_enable="NO"</programlisting>

	  <para>in <filename>/etc/rc.conf.</filename></para>

	<para>If you only want to disable
	  <application>sendmail</application>'s incoming mail service,
	  you should set</para>

	  <programlisting>sendmail_enable="NO"</programlisting>

	<para>in <filename>/etc/rc.conf</filename>.  More information on
	  <application>sendmail</application>'s startup options is
	  available from the &man.rc.sendmail.8; manual page.</para>
    </sect2>

    <sect2>
      <title>Running Your New MTA on Boot</title>

      <para>The new MTA can be started during boot by adding a
	configuration line to <filename>/etc/rc.conf</filename>
	like the following example for postfix:</para>

      <screen>&prompt.root; echo '<replaceable>postfix</replaceable>_enable=<quote>YES</quote>' &gt;&gt; /etc/rc.conf</screen>

      <para>The MTA will now be automatically started during
	boot.</para>
    </sect2>

    <sect2>
      <title>Replacing <application>sendmail</application> as
       the System's Default Mailer</title>

      <para>The program <application>sendmail</application> is so ubiquitous
	as standard software on &unix; systems that some software
	just assumes it is already installed and configured.
	For this reason, many alternative MTA's provide their own compatible
	implementations of the <application>sendmail</application>
	command-line interface; this facilitates using them as
	<quote>drop-in</quote> replacements for <application>sendmail</application>.</para>

      <para>Therefore, if you are using an alternative mailer,
	you will need to make sure that software trying to execute
	standard <application>sendmail</application> binaries such as
	<filename>/usr/bin/sendmail</filename> actually executes
	your chosen mailer instead.  Fortunately, FreeBSD provides
	a system called &man.mailwrapper.8; that does this job for
	you.</para>

      <para>When <application>sendmail</application> is operating as installed, you will
	find something like the following
	in <filename>/etc/mail/mailer.conf</filename>:</para>

<programlisting>sendmail	 /usr/libexec/sendmail/sendmail
send-mail	/usr/libexec/sendmail/sendmail
mailq		/usr/libexec/sendmail/sendmail
newaliases	/usr/libexec/sendmail/sendmail
hoststat	/usr/libexec/sendmail/sendmail
purgestat	/usr/libexec/sendmail/sendmail</programlisting>

      <para>This means that when any of these common commands
	(such as <filename>sendmail</filename> itself) are run,
	the system actually invokes a copy of mailwrapper named <filename>sendmail</filename>, which
	checks <filename>mailer.conf</filename> and
	executes <filename>/usr/libexec/sendmail/sendmail</filename>
	instead.  This system makes it easy to change what binaries
	are actually executed when these default <filename>sendmail</filename> functions
	are invoked.</para>

      <para>Therefore if you wanted
	<filename>/usr/local/supermailer/bin/sendmail-compat</filename>
	to be run instead of <application>sendmail</application>, you could change
	<filename>/etc/mail/mailer.conf</filename> to read:</para>

<programlisting>sendmail	 /usr/local/supermailer/bin/sendmail-compat
send-mail	/usr/local/supermailer/bin/sendmail-compat
mailq		/usr/local/supermailer/bin/mailq-compat
newaliases	/usr/local/supermailer/bin/newaliases-compat
hoststat	/usr/local/supermailer/bin/hoststat-compat
purgestat	/usr/local/supermailer/bin/purgestat-compat</programlisting>

	</sect2>

	<sect2>
	  <title>Finishing</title>

	<para>Once you have everything configured the way you want it, you should
	  either kill the <application>sendmail</application> processes that
	  you no longer need and start the processes belonging to your new
	  software, or simply reboot.  Rebooting will also
	  give you the opportunity to ensure that you have correctly
	  configured your system to start your new MTA automatically on boot.</para>

      </sect2>
    </sect1>

  <sect1 id="mail-trouble">
    <title>Troubleshooting</title>
    <indexterm>
      <primary>email</primary>
      <secondary>troubleshooting</secondary>
    </indexterm>

    <qandaset>
      <qandaentry>
        <question>
	<para>Why do I have to use the FQDN for hosts on my site?</para>
	</question>

	<answer>
	<para>You will probably find that the host is actually in a
	  different domain; for example, if you are in
	  <hostid role="fqdn">foo.bar.edu</hostid> and you wish to reach
	  a host called <hostid>mumble</hostid> in the <hostid
	  role="domainname">bar.edu</hostid> domain, you will have to
	  refer to it by the fully-qualified domain name, <hostid
	  role="fqdn">mumble.bar.edu</hostid>, instead of just
	  <hostid>mumble</hostid>.</para>

	<indexterm><primary>BIND</primary></indexterm>
	<para>Traditionally, this was allowed by BSD BIND resolvers.
	  However the current version of <application>BIND</application>
	  that ships with FreeBSD no longer provides default abbreviations
	  for non-fully qualified domain names other than the domain you
	  are in. So an unqualified host <hostid>mumble</hostid> must
	  either be found as <hostid
	  role="fqdn">mumble.foo.bar.edu</hostid>, or it will be searched
	  for in the root domain.</para>

        <para>This is different from the previous behavior, where the
	  search continued across <hostid
	  role="domainname">mumble.bar.edu</hostid>, and <hostid
	  role="domainname">mumble.edu</hostid>. Have a look at RFC 1535
	  for why this was considered bad practice, or even a security
	  hole.</para>

        <para>As a good workaround, you can place the line:

          <programlisting>search foo.bar.edu bar.edu</programlisting>

          instead of the previous:

          <programlisting>domain foo.bar.edu</programlisting>

          into your <filename>/etc/resolv.conf</filename>.  However, make
	  sure that the search order does not go beyond the
	  <quote>boundary between local and public administration</quote>,
	  as RFC 1535 calls it.</para>
	</answer>
      </qandaentry>

      <indexterm>
	<primary>MX record</primary>
      </indexterm>

      <qandaentry>
	<question>
	<para><application>sendmail</application> says <errorname>mail
	  loops back to myself</errorname></para>
	</question>

	<answer>
	<para>This is answered in the
	<application>sendmail</application> FAQ as follows:</para>

        <programlisting>I'm getting these error messages:

553 MX list for domain.net points back to relay.domain.net
554 &lt;user@domain.net&gt;... Local configuration error

How can I solve this problem?

You have asked mail to the domain (e.g., domain.net) to be
forwarded to a specific host (in this case, relay.domain.net)
by using an MX record, but the relay machine does not recognize
itself as domain.net. Add domain.net to /etc/mail/local-host-names
[known as /etc/sendmail.cw prior to version 8.10]
(if you are using FEATURE(use_cw_file)) or add <quote>Cw domain.net</quote>
to /etc/mail/sendmail.cf.</programlisting>

        <para>The <application>sendmail</application> FAQ can be found at
	  <ulink url="http://www.sendmail.org/faq/"></ulink> and is
	  recommended reading if you want to do any
	  <quote>tweaking</quote> of your mail setup.</para>
	</answer>
      </qandaentry>

      <indexterm><primary>PPP</primary></indexterm>
      <qandaentry>
        <question>
	<para>How can I run a mail server on a dial-up PPP host?</para>
	</question>

	<answer>
	<para>You want to connect a FreeBSD box on a LAN to the
	  Internet.  The FreeBSD box will be a mail gateway for the LAN.
	  The PPP connection is non-dedicated.</para>

	<indexterm><primary>UUCP</primary></indexterm>
	<indexterm>
	  <primary>MX record</primary>
	</indexterm>

	<para>There are at least two ways to do this.  One way is to use
	  UUCP.</para>

	<para>Another way is to get a full-time Internet server to provide secondary MX
	  services for your domain.  For example, if your company's domain is
	  <hostid role="domainname">example.com</hostid> and your Internet service provider has
	  set <hostid role="domainname">example.net</hostid> up to provide secondary MX services
	  to your domain:</para>

	<programlisting>example.com.          MX        10      example.com.
                      MX        20      example.net.</programlisting>

	<para>Only one host should be specified as the final recipient
	  (add <literal>Cw example.com</literal> in
	  <filename>/etc/mail/sendmail.cf</filename> on <hostid role="domainname">example.com</hostid>).</para>

	<para>When the sending <command>sendmail</command> is trying to
	  deliver the mail it will try to connect to you (<hostid role="domainname">example.com</hostid>) over the modem
	  link.  It will most likely time out because you are not online.
	  The program <application>sendmail</application> will automatically deliver it to the
	  secondary MX site, i.e. your Internet provider (<hostid role="domainname">example.net</hostid>).  The secondary MX
	  site will then periodically try to connect to
	  your host and deliver the mail to the primary MX host (<hostid role="domainname">example.com</hostid>).</para>

	<para>You might want to use something like this as a login
	  script:</para>

	<programlisting>#!/bin/sh
# Put me in /usr/local/bin/pppmyisp
( sleep 60 ; /usr/sbin/sendmail -q ) &amp;
/usr/sbin/ppp -direct pppmyisp</programlisting>

	<para>If you are going to create a separate login script for a
	  user you could use <command>sendmail -qRexample.com</command>
	  instead in the script above. This will force all mail in your
	  queue for <hostid role="domainname">example.com</hostid> to be processed immediately.</para>

	<para>A further refinement of the situation is as follows:</para>

	<para>Message stolen from the &a.isp;.</para>

	<programlisting>&gt; we provide the secondary MX for a customer. The customer connects to
&gt; our services several times a day automatically to get the mails to
&gt; his primary MX (We do not call his site when a mail for his domains
&gt; arrived). Our sendmail sends the mailqueue every 30 minutes. At the
&gt; moment he has to stay 30 minutes online to be sure that all mail is
&gt; gone to the primary MX.
&gt;
&gt; Is there a command that would initiate sendmail to send all the mails
&gt; now? The user has not root-privileges on our machine of course.

In the <quote>privacy flags</quote> section of sendmail.cf, there is a
definition Opgoaway,restrictqrun

Remove restrictqrun to allow non-root users to start the queue processing.
You might also like to rearrange the MXs. We are the 1st MX for our
customers like this, and we have defined:

# If we are the best MX for a host, try directly instead of generating
# local config error.
OwTrue

That way a remote site will deliver straight to you, without trying
the customer connection.  You then send to your customer.  Only works for
<quote>hosts</quote>, so you need to get your customer to name their mail
machine <quote>customer.com</quote> as well as
<quote>hostname.customer.com</quote> in the DNS.  Just put an A record in
the DNS for <quote>customer.com</quote>.</programlisting>
        </answer>
      </qandaentry>

      <qandaentry>
        <question>
	  <para>Why do I keep getting <errorname>Relaying
	    Denied</errorname> errors when sending mail from other
	    hosts?</para>
	</question>

	<answer>
	  <para>In default FreeBSD installations,
 	    <application>sendmail</application> is configured to only
 	    send mail from the host it is running on.  For example, if
	    a <acronym>POP</acronym> server is available, then users
	    will be able to check mail from school, work, or other
	    remote locations but they still will not be able to send
	    outgoing emails from outside locations.  Typically, a few
	    moments after the attempt, an email will be sent from
	    <application>MAILER-DAEMON</application> with a
	    <errorname>5.7 Relaying Denied</errorname> error
	    message.</para>

	  <para>There are several ways to get around this.  The most
 	    straightforward solution is to put your ISP's address in
 	    a relay-domains file at
 	    <filename>/etc/mail/relay-domains</filename>.  A quick way
 	    to do this would be:</para>

	  <screen>&prompt.root; <userinput>echo "your.isp.example.com" &gt; /etc/mail/relay-domains</userinput></screen>

	  <para>After creating or editing this file you must restart
  	    <application>sendmail</application>.  This works great if
  	    you are a server administrator and do not wish to send mail
  	    locally, or would like to use a point and click
  	    client/system on another machine or even another ISP.  It
  	    is also very useful if you only have one or two email
  	    accounts set up.  If there is a large number of addresses
  	    to add, you can simply open this file in your favorite
  	    text editor and then add the domains, one per line:</para>

	  <programlisting>your.isp.example.com
other.isp.example.net
users-isp.example.org
www.example.org</programlisting>

	  <para>Now any mail sent through your system, by any host in
	    this list (provided the user has an account on your
	    system), will succeed.  This is a very nice way to allow
	    users to send mail from your system remotely without
	    allowing people to send SPAM through your system.</para>

	</answer>
      </qandaentry>
    </qandaset>
  </sect1>

  <sect1 id="mail-advanced">
    <title>Advanced Topics</title>

    <para>The following section covers more involved topics such as mail
      configuration and setting up mail for your entire domain.</para>

    <sect2 id="mail-config">
      <title>Basic Configuration</title>
      <indexterm>
        <primary>email</primary>
        <secondary>configuration</secondary>
      </indexterm>

      <para>Out of the box, you should be able to send email to external
        hosts as long as you have set up
	<filename>/etc/resolv.conf</filename> or are running your own
	name server.  If you would like to have mail for your host
	delivered to the MTA (e.g., <application>sendmail</application>) on your own FreeBSD host, there are two methods:</para>

      <itemizedlist>
        <listitem>
          <para>Run your own name server and have your own domain.  For
	    example, <hostid
	    role="domainname">FreeBSD.org</hostid></para>
        </listitem>

        <listitem>
          <para>Get mail delivered directly to your host.  This is done by
	    delivering mail directly to the current DNS name for your
	    machine.  For example, <hostid
	    role="fqdn">example.FreeBSD.org</hostid>.</para>
        </listitem>
      </itemizedlist>

      <indexterm><primary>SMTP</primary></indexterm>
      <para>Regardless of which of the above you choose, in order to have
        mail delivered directly to your host, it must have a permanent
        static IP address (not a dynamic address, as with most PPP dial-up configurations).  If you are behind a
        firewall, it must pass SMTP traffic on to you.  If you want to
        receive mail directly at your host, you need to be sure of either of two
        things:</para>

      <itemizedlist>
        <indexterm><primary>MX record</primary></indexterm>
        <listitem>
          <para>Make sure that the (lowest-numbered) MX record in your DNS points to your
	    host's IP address.</para>
        </listitem>

        <listitem>
          <para>Make sure there is no MX entry in your DNS for your
	    host.</para>
        </listitem>
      </itemizedlist>

      <para>Either of the above will allow you to receive mail directly at
        your host.</para>

      <para>Try this:</para>

      <screen>&prompt.root; <userinput>hostname</userinput>
example.FreeBSD.org
&prompt.root; <userinput>host example.FreeBSD.org</userinput>
example.FreeBSD.org has address 204.216.27.XX</screen>

      <para>If that is what you see, mail directly to
        <email role="nolink">yourlogin@example.FreeBSD.org</email> should work without
        problems (assuming <application>sendmail</application> is
        running correctly on <hostid role="fqdn">example.FreeBSD.org</hostid>).</para>

      <para>If instead you see something like this:</para>

      <screen>&prompt.root; <userinput>host example.FreeBSD.org</userinput>
example.FreeBSD.org has address 204.216.27.XX
example.FreeBSD.org mail is handled (pri=10) by hub.FreeBSD.org</screen>

      <para>All mail sent to your host (<hostid
        role="fqdn">example.FreeBSD.org</hostid>) will end up being
	collected on <hostid>hub</hostid> under the same username instead
	of being sent directly to your host.</para>

      <para>The above information is handled by your DNS server.  The DNS
        record that carries mail routing information is the
        <emphasis>M</emphasis>ail e<emphasis>X</emphasis>change entry.  If
        no MX record exists, mail will be delivered directly to the host by
        way of its IP address.</para>

      <para>The MX entry for <hostid
        role="fqdn">freefall.FreeBSD.org</hostid> at one time looked like
        this:</para>

      <programlisting>freefall		MX	30	mail.crl.net
freefall		MX	40	agora.rdrop.com
freefall		MX	10	freefall.FreeBSD.org
freefall		MX	20	who.cdrom.com</programlisting>

      <para>As you can see, <hostid>freefall</hostid> had many MX entries.
        The lowest MX number is the host that receives mail directly if
        available; if it is not accessible for some reason, the others
        (sometimes called <quote>backup MXes</quote>) accept messages
        temporarily, and pass it along when a lower-numbered host becomes
        available, eventually to the lowest-numbered host.</para>

      <para>Alternate MX sites should have separate Internet connections
        from your own in order to be most useful.  Your ISP or another
        friendly site should have no problem providing this service for
        you.</para>
    </sect2>

    <sect2 id="mail-domain">
      <title>Mail for Your Domain</title>

      <para>In order to set up a <quote>mailhost</quote> (aka mail
        server) you need to have any mail sent to various workstations
	directed to it.  Basically, you want to <quote>claim</quote> any
	mail for any hostname in your domain (in this case <hostid
	role="fqdn">*.FreeBSD.org</hostid>) and divert it to your mail
	server so your users can receive their mail on
	the master mail server.</para>

      <indexterm><primary>DNS</primary></indexterm>
      <para>To make life easiest, a user account with the same
        <emphasis>username</emphasis> should exist on both machines.  Use
	&man.adduser.8; to do this.</para>

      <para>The mailhost you will be using must be the designated mail
        exchanger for each workstation on the network.  This is done in
	your DNS configuration like so:</para>

      <programlisting>example.FreeBSD.org	A	204.216.27.XX		; Workstation
			MX	10 hub.FreeBSD.org	; Mailhost</programlisting>

      <para>This will redirect mail for the workstation to the mailhost no
        matter where the A record points.  The mail is sent to the MX
	host.</para>

      <para>You cannot do this yourself unless you are running a DNS
        server.  If you are not, or cannot run your own DNS server, talk
	to your ISP or whoever provides your DNS.</para>

      <para>If you are doing virtual email hosting, the following
        information will come in handy.  For this example, we
	will assume you have a customer with his own domain, in this
	case <hostid role="domainname">customer1.org</hostid>, and you want
	all the mail for <hostid role="domainname">customer1.org</hostid>
	sent to your mailhost, <hostid
	role="fqdn">mail.myhost.com</hostid>.  The entry in your DNS
	should look like this:</para>

      <programlisting>customer1.org		MX	10	mail.myhost.com</programlisting>

      <para>You do <emphasis>not</emphasis> need an A record for <hostid role="domainname">customer1.org</hostid> if you only
        want to handle email for that domain.</para>

      <note>
	<para>Be aware that pinging <hostid
	  role="domainname">customer1.org</hostid> will not work unless
	  an A record exists for it.</para>
      </note>

      <para>The last thing that you must do is tell
        <application>sendmail</application> on your mailhost what domains
	and/or hostnames it should be accepting mail for.  There are a few
	different ways this can be done.  Either of the following will
	work:</para>

      <itemizedlist>
        <listitem>
	  <para>Add the hosts to your
	  <filename>/etc/mail/local-host-names</filename> file if you are using the
	  <literal>FEATURE(use_cw_file)</literal>.  If you are using
	  a version of <application>sendmail</application> earlier than 8.10, the file is
	  <filename>/etc/sendmail.cw</filename>.</para>
	</listitem>

	<listitem>
	  <para>Add a <literal>Cwyour.host.com</literal> line to your
	    <filename>/etc/sendmail.cf</filename> or
	    <filename>/etc/mail/sendmail.cf</filename> if you are using
	    <application>sendmail</application> 8.10 or higher.</para>
	</listitem>
      </itemizedlist>
    </sect2>
  </sect1>

  <sect1 id="SMTP-UUCP">
  <title>SMTP with UUCP</title>

    <para>The <application>sendmail</application> configuration that ships with FreeBSD is
      designed for sites that connect directly to the Internet.  Sites
      that wish to exchange their mail via UUCP must install another
      <application>sendmail</application> configuration file.</para>

    <para>Tweaking <filename>/etc/mail/sendmail.cf</filename> manually
      is an advanced topic. <application>sendmail</application> version 8 generates config files
      via &man.m4.1; preprocessing, where the actual configuration
      occurs on a higher abstraction level. The &man.m4.1;
      configuration files can be found under
      <filename>/usr/share/sendmail/cf</filename>.  The file
      <filename>README</filename> in the <filename>cf</filename>
      directory can serve as a basic introduction to &man.m4.1;
      configuration.</para>

    <para>The best way to support UUCP delivery is to use the
      <literal>mailertable</literal> feature.  This creates a database
      that <application>sendmail</application> can use to make routing decisions.</para>

    <para>First, you have to create your <filename>.mc</filename>
      file.  The directory
      <filename>/usr/share/sendmail/cf/cf</filename> contains a
      few examples.  Assuming you have named your file
      <filename>foo.mc</filename>, all you need to do in order to
      convert it into a valid <filename>sendmail.cf</filename>
      is:</para>

    <screen>&prompt.root; <userinput>cd /etc/mail</userinput>
&prompt.root; <userinput>make foo.cf</userinput>
&prompt.root; <userinput>cp foo.cf /etc/mail/sendmail.cf</userinput></screen>

    <para>A typical <filename>.mc</filename> file might look
        like:</para>

    <programlisting>VERSIONID(`<replaceable>Your version number</replaceable>') OSTYPE(bsd4.4)

FEATURE(accept_unresolvable_domains)
FEATURE(nocanonify)
FEATURE(mailertable, `hash -o /etc/mail/mailertable')

define(`UUCP_RELAY', <replaceable>your.uucp.relay</replaceable>)
define(`UUCP_MAX_SIZE', 200000)
define(`confDONT_PROBE_INTERFACES')

MAILER(local)
MAILER(smtp)
MAILER(uucp)

Cw    <replaceable>your.alias.host.name</replaceable>
Cw    <replaceable>youruucpnodename.UUCP</replaceable></programlisting>

    <para>The lines containing
      <literal>accept_unresolvable_domains</literal>,
      <literal>nocanonify</literal>, and
      <literal>confDONT_PROBE_INTERFACES</literal> features will
      prevent any usage of the DNS during mail delivery.  The
      <literal>UUCP_RELAY</literal> clause is needed to support UUCP
      delivery.  Simply put an Internet hostname there that is able to
      handle .UUCP pseudo-domain addresses; most likely, you will
      enter the mail relay of your ISP there.</para>

    <para>Once you have this, you need an
      <filename>/etc/mail/mailertable</filename> file.  If you have
      only one link to the outside that is used for all your mails,
      the following file will suffice:</para>

    <programlisting>#
# makemap hash /etc/mail/mailertable.db &lt; /etc/mail/mailertable
.                             uucp-dom:<replaceable>your.uucp.relay</replaceable></programlisting>

    <para>A more complex example might look like this:</para>

    <programlisting>#
# makemap hash /etc/mail/mailertable.db &lt; /etc/mail/mailertable
#
horus.interface-business.de   uucp-dom:horus
.interface-business.de        uucp-dom:if-bus
interface-business.de         uucp-dom:if-bus
.heep.sax.de                  smtp8:%1
horus.UUCP                    uucp-dom:horus
if-bus.UUCP                   uucp-dom:if-bus
.                             uucp-dom:</programlisting>


    <para>The first three lines handle special cases where
      domain-addressed mail should not be sent out to the default
      route, but instead to some UUCP neighbor in order to
      <quote>shortcut</quote> the delivery path. The next line handles
      mail to the local Ethernet domain that can be delivered using
      SMTP. Finally, the UUCP neighbors are mentioned in the .UUCP
      pseudo-domain notation, to allow for a
      <literal><replaceable>uucp-neighbor
      </replaceable>!<replaceable>recipient</replaceable></literal>
      override of the default rules. The last line is always a single
      dot, matching everything else, with UUCP delivery to a UUCP
      neighbor that serves as your universal mail gateway to the
      world. All of the node names behind the
      <literal>uucp-dom:</literal> keyword must be valid UUCP
      neighbors, as you can verify using the command
      <literal>uuname</literal>.</para>

    <para>As a reminder that this file needs to be converted into a
      DBM database file before use.  The command line to accomplish
      this is best placed as a comment at the top of the <filename>mailertable</filename> file.
      You always have to execute this command each time you change
      your <filename>mailertable</filename> file.</para>

    <para>Final hint: if you are uncertain whether some particular
      mail routing would work, remember the <option>-bt</option>
      option to <application>sendmail</application>. It starts <application>sendmail</application> in <emphasis>address test
      mode</emphasis>; simply enter <literal>3,0</literal>, followed
      by the address you wish to test for the mail routing.  The last
      line tells you the used internal mail agent, the destination
      host this agent will be called with, and the (possibly
      translated) address. Leave this mode by typing <keycombo
      action="simul"><keycap>Ctrl</keycap><keycap>D</keycap></keycombo>.</para>

    <screen>&prompt.user; <userinput>sendmail -bt</userinput>
ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
Enter &lt;ruleset&gt; &lt;address&gt;
<prompt>&gt;</prompt> <userinput>3,0 foo@example.com</userinput>
canonify           input: foo @ example . com
...
parse            returns: $# uucp-dom $@ <replaceable>your.uucp.relay</replaceable> $: foo &lt; @ example . com . &gt;
<prompt>&gt;</prompt> <userinput>^D</userinput></screen>
  </sect1>

  <sect1 id="outgoing-only">
    <sect1info>
      <authorgroup>
        <author>
          <firstname>Bill</firstname>
          <surname>Moran</surname>
          <contrib>Contributed by </contrib>
        </author>
      </authorgroup>
    </sect1info>

    <title>Setting Up to Send Only</title>

    <para>There are many instances where you may only want to send
      mail through a relay.  Some examples are:</para>

    <itemizedlist>
      <listitem>
	<para>Your computer is a desktop machine, but you want
	  to use programs such as &man.send-pr.1;.  To do so, you should use
	  your ISP's mail relay.</para>
      </listitem>

      <listitem>
	<para>The computer is a server that does not handle mail
	  locally, but needs to pass off all mail to a relay for
	  processing.</para>
      </listitem>
    </itemizedlist>

    <para>Just about any <acronym>MTA</acronym> is capable of filling
      this particular niche.  Unfortunately, it can be very difficult
      to properly configure a full-featured <acronym>MTA</acronym>
      just to handle offloading mail.  Programs such as
      <application>sendmail</application> and
      <application>postfix</application> are largely overkill for
      this use.</para>

    <para>Additionally, if you are using a typical Internet access
      service, your agreement may forbid you from running a
      <quote>mail server</quote>.</para>

    <para>The easiest way to fulfill those needs is to install the
      <filename role="package">mail/ssmtp</filename> port.  Execute
      the following commands as <username>root</username>:</para>

    <screen>&prompt.root; <userinput>cd /usr/ports/mail/ssmtp</userinput>
&prompt.root; <userinput>make install replace clean</userinput></screen>

    <para>Once installed,
      <filename role="package">mail/ssmtp</filename> can be configured
      with a four-line file located at
      <filename>/usr/local/etc/ssmtp/ssmtp.conf</filename>:</para>

    <programlisting>root=yourrealemail@example.com
mailhub=mail.example.com
rewriteDomain=example.com
hostname=_HOSTNAME_</programlisting>

    <para>Make sure you use your real email address for
      <username>root</username>.  Enter your ISP's outgoing mail relay
      in place of <hostid role="fqdn">mail.example.com</hostid> (some ISPs call
      this the <quote>outgoing mail server</quote> or
      <quote>SMTP server</quote>).</para>

    <para>Make sure you disable <application>sendmail</application>,
      including the outgoing mail service. See
      <xref linkend="mail-disable-sendmail"> for details.</para>

    <para><filename role="package">mail/ssmtp</filename> has some
      other options available.  See the example configuration file in
      <filename>/usr/local/etc/ssmtp</filename> or the manual page of
      <application>ssmtp</application> for some examples and more
      information.</para>

    <para>Setting up <application>ssmtp</application> in this manner
      will allow any software on your computer that needs to send
      mail to function properly, while not violating your ISP's usage
      policy or allowing your computer to be hijacked for spamming.</para>
  </sect1>

  <sect1 id="SMTP-dialup">
    <title>Using Mail with a Dialup Connection</title>

    <para>If you have a static IP address, you should not need to
      adjust anything from the defaults.  Set your host name to your
      assigned Internet name and <application>sendmail</application> will do the rest.</para>

    <para>If you have a dynamically assigned IP number and use a
      dialup PPP connection to the Internet, you will probably have a
      mailbox on your ISPs mail server. Let's assume your ISP's domain
      is <hostid role="domainname">example.net</hostid>, and that your
      user name is <username>user</username>, you have called your
      machine <hostid role="fqdn">bsd.home</hostid>, and your ISP has
      told you that you may use <hostid
      role="fqdn">relay.example.net</hostid> as a mail relay.</para>

    <para>In order to retrieve mail from your mailbox, you must
      install a retrieval agent.  The
      <application>fetchmail</application> utility is a good choice as
      it supports many different protocols.  This program is available
      as a package or from the Ports Collection (<filename
      role="package">mail/fetchmail</filename>).  Usually, your <acronym>ISP</acronym> will
      provide <acronym>POP</acronym>. If you are using user <acronym>PPP</acronym>, you can
      automatically fetch your mail when an Internet connection is
      established with the following entry in
      <filename>/etc/ppp/ppp.linkup</filename>:</para>

    <programlisting>MYADDR:
!bg su user -c fetchmail</programlisting>

    <para>If you are using <application>sendmail</application> (as
      shown below) to deliver mail to non-local accounts, you probably
      want to have <application>sendmail</application> process your
      mailqueue as soon as your Internet connection is established.
      To do this, put this command after the
      <command>fetchmail</command> command in
      <filename>/etc/ppp/ppp.linkup</filename>:</para>

    <programlisting>  !bg su user -c "sendmail -q"</programlisting>

    <para>Assume that you have an account for
      <username>user</username> on <hostid
      role="fqdn">bsd.home</hostid>. In the home directory of
      <username>user</username> on <hostid
      role="fqdn">bsd.home</hostid>, create a
      <filename>.fetchmailrc</filename> file:</para>

    <programlisting>poll example.net protocol pop3 fetchall pass MySecret</programlisting>

    <para>This file should not be readable by anyone except
      <username>user</username> as it contains the password
      <literal>MySecret</literal>.</para>

    <para>In order to send mail with the correct
      <literal>from:</literal> header, you must tell
      <application>sendmail</application> to use
      <email>user@example.net</email> rather than
      <email role="nolink">user@bsd.home</email>. You may also wish to tell
      <application>sendmail</application> to send all mail via <hostid
      role="fqdn">relay.example.net</hostid>, allowing quicker mail
      transmission.</para>

    <para>The following <filename>.mc</filename> file should
      suffice:</para>

    <programlisting>VERSIONID(`bsd.home.mc version 1.0')
OSTYPE(bsd4.4)dnl
FEATURE(nouucp)dnl
MAILER(local)dnl
MAILER(smtp)dnl
Cwlocalhost
Cwbsd.home
MASQUERADE_AS(`example.net')dnl
FEATURE(allmasquerade)dnl
FEATURE(masquerade_envelope)dnl
FEATURE(nocanonify)dnl
FEATURE(nodns)dnl
define(`SMART_HOST', `relay.example.net')
Dmbsd.home
define(`confDOMAIN_NAME',`bsd.home')dnl
define(`confDELIVERY_MODE',`deferred')dnl</programlisting>

    <para>Refer to the previous section for details of how to turn
      this <filename>.mc</filename> file into a
      <filename>sendmail.cf</filename> file.  Also, do not forget to
      restart <application>sendmail</application> after updating
      <filename>sendmail.cf</filename>.</para>
  </sect1>

  <sect1 id="SMTP-Auth">
    <sect1info>
    <authorgroup>
      <author>
        <firstname>James</firstname>
        <surname>Gorham</surname>
        <contrib>Written by </contrib>
      </author>
    </authorgroup>
    </sect1info>

    <title>SMTP Authentication</title>

    <para>Having <acronym>SMTP</acronym> Authentication in place on
      your mail server has a number of benefits.
      <acronym>SMTP</acronym> Authentication can add another layer
      of security to <application>sendmail</application>, and has the benefit of giving mobile
      users who switch hosts the ability to use the same mail server
      without the need to reconfigure their mail client settings
      each time.</para>

    <procedure>
      <step>
	<para>Install <filename role="package">security/cyrus-sasl2</filename>
	  from the ports. You can find this port in
	  <filename role="package">security/cyrus-sasl2</filename>.  The
	  <filename role="package">security/cyrus-sasl2</filename> port
	  supports a number of compile-time options.  For the SMTP
	  Authentication method we will be using here, make sure that
	  the <option>LOGIN</option> option is not disabled.</para>
      </step>


      <step>
	<para>After installing <filename role="package">security/cyrus-sasl2</filename>,
	  edit <filename>/usr/local/lib/sasl2/Sendmail.conf</filename>
	  (or create it if it does not exist) and add the following
	  line:</para>

	<programlisting>pwcheck_method: saslauthd</programlisting>
      </step>

      <step>
	<para>Next, install <filename role="package">security/cyrus-sasl2-saslauthd</filename>,
	  edit <filename>/etc/rc.conf</filename> to add the following
	  line:</para>

	<programlisting>saslauthd_enable="YES"</programlisting>

	<para>and finally start the saslauthd daemon:</para>

	<screen>&prompt.root; <userinput>/usr/local/etc/rc.d/saslauthd start</userinput></screen>

	<para>This daemon serves as a broker for <application>sendmail</application> to
	  authenticate against your FreeBSD <filename>passwd</filename>
	  database.  This saves the trouble of creating a new set of usernames
	  and passwords for each user that needs to use
	  <acronym>SMTP</acronym> authentication, and keeps the login
	  and mail password the same.</para>
      </step>

      <step>
	<para>Now edit <filename>/etc/make.conf</filename> and add the
	  following lines:</para>

	<programlisting>SENDMAIL_CFLAGS=-I/usr/local/include/sasl -DSASL
SENDMAIL_LDFLAGS=-L/usr/local/lib
SENDMAIL_LDADD=-lsasl2</programlisting>

	<para>These lines will give <application>sendmail</application>
	the proper configuration options for linking
	to <filename role="package">cyrus-sasl2</filename> at compile time.
	Make sure that <filename role="package">cyrus-sasl2</filename>
	has been installed before recompiling
	<application>sendmail</application>.</para>
      </step>

      <step>
	<para>Recompile <application>sendmail</application> by executing the following commands:</para>

	<screen>&prompt.root; <userinput>cd /usr/src/lib/libsmutil</userinput>
&prompt.root; <userinput>make cleandir && make obj && make</userinput>
&prompt.root; <userinput>cd /usr/src/lib/libsm</userinput>
&prompt.root; <userinput>make cleandir && make obj && make</userinput>
&prompt.root; <userinput>cd /usr/src/usr.sbin/sendmail</userinput>
&prompt.root; <userinput>make cleandir && make obj && make && make install</userinput></screen>

	<para>The compile of <application>sendmail</application> should not have any problems
	  if <filename>/usr/src</filename> has not been changed extensively
	  and the shared libraries it needs are available.</para>
      </step>

      <step>
	<para>After <application>sendmail</application> has been compiled
	  and reinstalled, edit your <filename>/etc/mail/freebsd.mc</filename>
	  file (or whichever file you use as your <filename>.mc</filename> file. Many administrators
	  choose to use the output from &man.hostname.1; as the <filename>.mc</filename> file for
	  uniqueness).  Add these lines to it:</para>

	<programlisting>dnl set SASL options
TRUST_AUTH_MECH(`GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN')dnl
define(`confAUTH_MECHANISMS', `GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN')dnl</programlisting>

	<para>These options configure the different methods available to
	<application>sendmail</application> for authenticating users.
	If you would like to use a method other than
	<application>pwcheck</application>, please see the
	included documentation.</para>
      </step>

      <step>
	<para>Finally, run &man.make.1; while in <filename>/etc/mail</filename>.
	  That will run your new <filename>.mc</filename> file and create a <filename>.cf</filename> file named
	  <filename>freebsd.cf</filename> (or whatever name you have used
	  for your <filename>.mc</filename> file).  Then use the
	  command <command>make install restart</command>, which will
	  copy the file to <filename>sendmail.cf</filename>, and will
	  properly restart <application>sendmail</application>.
	  For more information about this process, you should refer
	  to <filename>/etc/mail/Makefile</filename>.</para>
      </step>
    </procedure>

    <para>If all has gone correctly, you should be able to enter your login
      information into the mail client and send a test message.
      For further investigation, set the <option>LogLevel</option> of
      <application>sendmail</application> to 13 and watch
      <filename>/var/log/maillog</filename> for any errors.</para>

    <para>For more information, please see the <application>sendmail</application>
      page regarding
      <ulink url="http://www.sendmail.org/~ca/email/auth.html">
      <acronym>SMTP</acronym> authentication</ulink>.</para>

  </sect1>

  <sect1 id="mail-agents">
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Marc</firstname>
	  <surname>Silver</surname>
	  <contrib>Contributed by </contrib>
	</author>
      </authorgroup>
    </sect1info>
    <title>Mail User Agents</title>

    <indexterm>
      <primary>Mail User Agents</primary>
    </indexterm>

    <para>A Mail User Agent (<acronym>MUA</acronym>) is an application
      that is used to send and receive email.  Furthermore, as email
      <quote>evolves</quote> and becomes more complex,
      <acronym>MUA</acronym>'s are becoming increasingly powerful in the
      way they interact with email; this gives users increased
      functionality and flexibility.  &os; contains support for
      numerous mail user agents, all of which can be easily installed
      using the <link linkend="ports">FreeBSD Ports Collection</link>.
      Users may choose between graphical email clients such as
      <application>evolution</application> or
      <application>balsa</application>, console based clients such as
      <application>mutt</application>, <application>alpine</application>
      or <command>mail</command>, or the web interfaces used by some
      large organizations.</para>

    <sect2 id="mail-command">
      <title>mail</title>

      <para>&man.mail.1; is the default Mail User Agent
	(<acronym>MUA</acronym>) in &os;.  It is a
	console based <acronym>MUA</acronym> that offers all the basic
	functionality required to send and receive text-based email,
	though it is limited in interaction abilities with attachments
	and can only support local mailboxes.</para>

      <para>Although <command>mail</command> does not natively support
	interaction with <acronym>POP</acronym> or
	<acronym>IMAP</acronym> servers, these mailboxes may be
	downloaded to a local <filename>mbox</filename> file using an
	application such as <application>fetchmail</application>, which
	will be discussed later in this chapter (<xref
	linkend="mail-fetchmail">).</para>

      <para>In order to send and receive email, simply invoke the
	<command>mail</command> command as per the following
	example:</para>

      <screen>&prompt.user; <userinput>mail</userinput></screen>

      <para>The contents of the user mailbox in
	<filename class="directory">/var/mail</filename> are
	automatically read by the <command>mail</command> utility.
	Should the mailbox be empty, the utility exits with a
	message indicating that no mails could be found.  Once the
	mailbox has been read, the application interface is started, and
	a list of messages will be displayed.  Messages are automatically
	numbered, as can be seen in the following example:</para>

      <screen>Mail version 8.1 6/6/93.  Type ? for help.
"/var/mail/marcs": 3 messages 3 new
>N  1 root@localhost        Mon Mar  8 14:05  14/510   "test"
 N  2 root@localhost        Mon Mar  8 14:05  14/509   "user account"
 N  3 root@localhost        Mon Mar  8 14:05  14/509   "sample"</screen>

      <para>Messages can now be read by using the <keycap>t</keycap>
	<command>mail</command> command, suffixed by the message number
	that should be displayed.  In this example, we will read the
	first email:</para>

      <screen>&amp; <userinput>t 1</userinput>
Message 1:
From root@localhost  Mon Mar  8 14:05:52 2004
X-Original-To: marcs@localhost
Delivered-To: marcs@localhost
To: marcs@localhost
Subject: test
Date: Mon,  8 Mar 2004 14:05:52 +0200 (SAST)
From: root@localhost (Charlie Root)

This is a test message, please reply if you receive it.</screen>

      <para>As can be seen in the example above, the <keycap>t</keycap>
	key will cause the message to be displayed with full headers.
	To display the list of messages again, the <keycap>h</keycap>
	key should be used.</para>

      <para>If the email requires a response, you may use
	<command>mail</command> to reply, by using either the
	<keycap>R</keycap> or <keycap>r</keycap> <command>mail</command>
	keys.  The <keycap>R</keycap> key instructs
	<command>mail</command> to reply only to the sender of the
	email, while <keycap>r</keycap> replies not only to the sender,
	but also to other recipients of the message.  You may also
	suffix these commands with the mail number which you would like
	make a reply to.  Once this has been done, the response should
	be entered, and the end of the message should be marked by a
	single <keycap>.</keycap> on a new line.  An example can be seen
	below:</para>

      <screen>&amp; <userinput>R 1</userinput>
To: root@localhost
Subject: Re: test

<userinput>Thank you, I did get your email.
.</userinput>
EOT</screen>

      <para>In order to send new email, the <keycap>m</keycap>
	key should be used, followed by the
	recipient email address.  Multiple recipients may also be
	specified by separating each address with the <keycap>,</keycap>
	delimiter.  The subject of the message may then be entered,
	followed by the message contents.  The end of the message should
	be specified by putting a single <keycap>.</keycap> on a new
	line.</para>

      <screen>&amp; <userinput>mail root@localhost</userinput>
Subject: <userinput>I mastered mail

Now I can send and receive email using mail ... :)
.</userinput>
EOT</screen>

      <para>While inside the <command>mail</command> utility, the
	<keycap>?</keycap> command may be used to display help at any
	time, the &man.mail.1; manual page should also be consulted for
	more help with <command>mail</command>.</para>

      <note>
        <para>As previously mentioned, the &man.mail.1; command was not
	  originally designed to handle attachments, and thus deals with
	  them very poorly.  Newer <acronym>MUA</acronym>s such as
	  <application>mutt</application> handle attachments in a much
	  more intelligent way.  But should you still wish to use the
	  <command>mail</command> command, the <filename
	  role="package">converters/mpack</filename> port may be of
	  considerable use.</para>
      </note>
    </sect2>

    <sect2 id="mutt-command">
      <title>mutt</title>

      <para><application>mutt</application> is a small yet very
	 powerful Mail User Agent, with excellent features,
	 just some of which include:</para>

      <itemizedlist>
        <listitem>
	  <para>The ability to thread messages;</para>
        </listitem>

        <listitem>
	  <para>PGP support for digital signing and encryption of
	    email;</para>
        </listitem>

        <listitem>
	  <para>MIME Support;</para>
        </listitem>

        <listitem>
	  <para>Maildir Support;</para>
        </listitem>

        <listitem>
	  <para>Highly customizable.</para>
        </listitem>
      </itemizedlist>

      <para>All of these features help to make
	<application>mutt</application> one of the most advanced mail
	user agents available.  See <ulink
	url="http://www.mutt.org"></ulink> for more
	information on <application>mutt</application>.</para>

      <para>The stable version of <application>mutt</application> may be
	installed using the <filename
	role="package">mail/mutt</filename> port, while the current
	development version may be installed via the <filename
	role="package">mail/mutt-devel</filename> port.  After the port
	has been installed, <application>mutt</application> can be
	started by issuing the following command:</para>

      <screen>&prompt.user; <userinput>mutt</userinput></screen>

      <para><application>mutt</application> will automatically read the
	contents of the user mailbox in <filename
	class="directory">/var/mail</filename> and display the contents
	if applicable.  If no mails are found in the user mailbox, then
	<application>mutt</application> will wait for commands from the
	user.  The example below shows <application>mutt</application>
	displaying a list of messages:</para>

      <mediaobject>
	<imageobject>
	  <imagedata fileref="mail/mutt1" format="PNG">
	</imageobject>
      </mediaobject>

      <para>In order to read an email, simply select it using the cursor
	keys, and press the <keycap>Enter</keycap> key.  An example of
	<application>mutt</application> displaying email can be seen
	below:</para>

      <mediaobject>
	<imageobject>
	  <imagedata fileref="mail/mutt2" format="PNG">
	</imageobject>
      </mediaobject>

      <para>As with the &man.mail.1; command,
	<application>mutt</application> allows users to reply only to
	the sender of the message as well as to all recipients.  To
	reply only to the sender of the email, use the
	<keycap>r</keycap> keyboard shortcut.  To send a group reply,
	which will be sent to the original sender as well as all the
	message recipients, use the <keycap>g</keycap> shortcut.</para>

      <note>
	<para><application>mutt</application> makes use of the
	  &man.vi.1; command as an editor for creating and replying to
	  emails.  This may be customized by the user by creating or
	  editing their own <filename>.muttrc</filename> file in their home directory and setting the
	  <literal>editor</literal> variable or by setting the
	  <envar>EDITOR</envar> environment variable.  See
	  <ulink url="http://www.mutt.org/"></ulink> for more
	  information about configuring
	  <application>mutt</application>.</para>
      </note>

      <para>In order to compose a new mail message, press
	<keycap>m</keycap>.  After a valid subject has been given,
	<application>mutt</application> will start &man.vi.1; and the
	mail can be written.  Once the contents of the mail are
	complete, save and quit from <command>vi</command> and
	<application>mutt</application> will resume, displaying a
	summary screen of the mail that is to be delivered.  In order to
	send the mail, press <keycap>y</keycap>.  An example of the
	summary screen can be seen below:</para>

      <mediaobject>
	<imageobject>
	  <imagedata fileref="mail/mutt3" format="PNG">
	</imageobject>
      </mediaobject>

      <para><application>mutt</application> also contains extensive
	help, which can be accessed from most of the menus by pressing
	the <keycap>?</keycap> key.  The top line also displays the
	keyboard shortcuts where appropriate.</para>

    </sect2>

    <sect2 id="alpine-command">
      <title>alpine</title>

      <para><application>alpine</application> is aimed at a beginner
	user, but also includes some advanced features.</para>

      <warning>
	<para>The <application>alpine</application> software has had several remote vulnerabilities
	  discovered in the past, which allowed remote attackers to
	  execute arbitrary code as users on the local system, by the
	  action of sending a specially-prepared email. All such
	  <emphasis>known</emphasis> problems have been fixed, but the
	  <application>alpine</application> code is written in a very insecure style and the &os;
	  Security Officer believes there are likely to be other
	  undiscovered vulnerabilities. You install
	  <application>alpine</application> at your own risk.</para>
      </warning>

      <para>The current version of <application>alpine</application> may
	be installed using the <filename
	role="package">mail/alpine</filename> port.  Once the port has
	installed, <application>alpine</application> can be started by
	issuing the following command:</para>

      <screen>&prompt.user; <userinput>alpine</userinput></screen>

      <para>The first time that <application>alpine</application> is run
	it displays a greeting page with a brief introduction, as well
	as a request from the <application>alpine</application>
	development team to send an anonymous email message allowing
	them to judge how many users are using their client.  To send
	this anonymous message, press <keycap>Enter</keycap>, or
	alternatively press <keycap>E</keycap> to exit the greeting
	without sending an anonymous message.  An example of the
	greeting page can be seen below:</para>

      <mediaobject>
	<imageobject>
	  <imagedata fileref="mail/pine1" format="PNG">
	</imageobject>
      </mediaobject>

      <para>Users are then presented with the main menu, which can be
	easily navigated using the cursor keys.  This main menu provides
	shortcuts for the composing new mails, browsing of mail directories,
	and even the administration of address book entries.  Below the
	main menu, relevant keyboard shortcuts to perform functions
	specific to the task at hand are shown.</para>

      <para>The default directory opened by <application>alpine</application>
	is the <filename class="directory">inbox</filename>.  To view the message index, press
	<keycap>I</keycap>, or select the <guimenuitem>MESSAGE INDEX</guimenuitem>
	option as seen below:</para>

      <mediaobject>
	<imageobject>
	  <imagedata fileref="mail/pine2" format="PNG">
	</imageobject>
      </mediaobject>

      <para>The message index shows messages in the current directory,
	and can be navigated by using the cursor keys.  Highlighted
	messages can be read by pressing the
	<keycap>Enter</keycap> key.</para>

      <mediaobject>
	<imageobject>
	  <imagedata fileref="mail/pine3" format="PNG">
	</imageobject>
      </mediaobject>

      <para>In the screenshot below, a sample message is displayed by
	<application>alpine</application>.  Keyboard shortcuts are
	displayed as a reference at the bottom of the screen.  An
	example of one of these shortcuts is the <keycap>r</keycap> key,
	which tells the <acronym>MUA</acronym> to reply to the current
	message being displayed.</para>

      <mediaobject>
	<imageobject>
	  <imagedata fileref="mail/pine4" format="PNG">
	</imageobject>
      </mediaobject>

      <para>Replying to an email in <application>alpine</application> is
	done using the <application>pico</application> editor, which is
	installed by default with <application>alpine</application>.
	The <application>pico</application> utility makes it easy to
	navigate around the message and is slightly more forgiving on
	novice users than &man.vi.1; or &man.mail.1;.  Once the reply
	is complete, the message can be sent by pressing
	<keycombo action="simul"><keycap>Ctrl</keycap><keycap>X</keycap>
	</keycombo>. The <application>alpine</application> application
	will ask for confirmation.</para>

      <mediaobject>
	<imageobject>
	  <imagedata fileref="mail/pine5" format="PNG">
	</imageobject>
      </mediaobject>

      <para>The <application>alpine</application> application can be
	customized using the <guimenuitem>SETUP</guimenuitem> option from the main
	menu.  Consult <ulink url="http://www.washington.edu/alpine/"></ulink>
	for more information.</para>

    </sect2>
  </sect1>

  <sect1 id="mail-fetchmail">
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Marc</firstname>
	  <surname>Silver</surname>
	  <contrib>Contributed by </contrib>
	</author>
      </authorgroup>
    </sect1info>
    <title>Using fetchmail</title>

    <indexterm>
      <primary>fetchmail</primary>
    </indexterm>

    <para><application>fetchmail</application> is a full-featured
      <acronym>IMAP</acronym> and <acronym>POP</acronym> client which
      allows users to automatically download mail from remote
      <acronym>IMAP</acronym> and <acronym>POP</acronym> servers and
      save it into local mailboxes; there it can be accessed more easily.
      <application>fetchmail</application> can be installed using the
      <filename role="package">mail/fetchmail</filename> port, and
      offers various features, some of which include:</para>

    <itemizedlist>
      <listitem>
	<para>Support of <acronym>POP3</acronym>,
	  <acronym>APOP</acronym>, <acronym>KPOP</acronym>,
	  <acronym>IMAP</acronym>, <acronym>ETRN</acronym> and
	  <acronym>ODMR</acronym> protocols.</para>
      </listitem>

      <listitem>
	<para>Ability to forward mail using <acronym>SMTP</acronym>, which
	  allows filtering, forwarding, and aliasing to function
	  normally.</para>
      </listitem>

      <listitem>
	<para>May be run in daemon mode to check periodically for new
	  messages.</para>
      </listitem>

      <listitem>
	<para>Can retrieve multiple mailboxes and forward them based
	  on configuration, to different local users.</para>
      </listitem>
    </itemizedlist>

    <para>While it is outside the scope of this document to explain
      all of <application>fetchmail</application>'s features, some
      basic features will be explained.  The
      <application>fetchmail</application> utility requires a
      configuration file known as <filename>.fetchmailrc</filename>,
      in order to run correctly.  This file includes server information
      as well as login credentials.  Due to the sensitive nature of the
      contents of this file, it is advisable to make it readable only by the owner,
      with the following command:</para>

    <screen>&prompt.user; <userinput>chmod 600 .fetchmailrc</userinput></screen>

    <para>The following <filename>.fetchmailrc</filename> serves as an
      example for downloading a single user mailbox using
      <acronym>POP</acronym>.  It tells
      <application>fetchmail</application> to connect to <hostid
      role="fqdn">example.com</hostid> using a username of
      <username>joesoap</username> and a password of
      <literal>XXX</literal>.  This example assumes that the user
      <username>joesoap</username> is also a user on the local
      system.</para>

    <programlisting>poll example.com protocol pop3 username "joesoap" password "XXX"</programlisting>

    <para>The next example connects to multiple <acronym>POP</acronym>
      and <acronym>IMAP</acronym> servers and redirects to different
      local usernames where applicable:</para>

    <programlisting>poll example.com proto pop3:
user "joesoap", with password "XXX", is "jsoap" here;
user "andrea", with password "XXXX";
poll example2.net proto imap:
user "john", with password "XXXXX", is "myth" here;</programlisting>

    <para>The <application>fetchmail</application> utility can be run in daemon
      mode by running it with the <option>-d</option> flag, followed
      by the interval (in seconds) that
      <application>fetchmail</application> should poll servers listed
      in the <filename>.fetchmailrc</filename> file.  The following
      example would cause <application>fetchmail</application> to poll
      every 600 seconds:</para>

    <screen>&prompt.user; <userinput>fetchmail -d 600</userinput></screen>

    <para>More information on <application>fetchmail</application> can
      be found at <ulink
      url="http://fetchmail.berlios.de/"></ulink>.</para>
  </sect1>

  <sect1 id="mail-procmail">
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Marc</firstname>
	  <surname>Silver</surname>
	  <contrib>Contributed by </contrib>
	</author>
      </authorgroup>
    </sect1info>
    <title>Using procmail</title>

    <indexterm>
      <primary>procmail</primary>
    </indexterm>

    <para>The <application>procmail</application> utility is an
      incredibly powerful application used to filter incoming mail.
      It allows users to define <quote>rules</quote> which can be
      matched to incoming mails to perform specific functions or to
      reroute mail to alternative mailboxes and/or email addresses.
      <application>procmail</application> can be installed using the
      <filename role="package">mail/procmail</filename> port.  Once
      installed, it can be directly integrated into most
      <acronym>MTA</acronym>s; consult your <acronym>MTA</acronym>
      documentation for more information.  Alternatively,
      <application>procmail</application> can be integrated by adding
      the following line to a <filename>.forward</filename> in the home
      directory of the user utilizing
      <application>procmail</application> features:</para>

    <programlisting>"|exec /usr/local/bin/procmail || exit 75"</programlisting>

    <para>The following section will display some basic
      <application>procmail</application> rules, as well as brief
      descriptions on what they do.  These rules, and others must be
      inserted into a <filename>.procmailrc</filename> file, which
      must reside in the user's home directory.</para>

    <para>The majority of these rules can also be found in the
      &man.procmailex.5; manual page.</para>

    <para>Forward all mail from <email>user@example.com</email> to an
      external address of <email role="nolink">goodmail@example2.com</email>:</para>

    <programlisting>:0
* ^From.*user@example.com
! goodmail@example2.com</programlisting>

    <para>Forward all mails shorter than 1000 bytes to an external
      address of <email role="nolink">goodmail@example2.com</email>:</para>

    <programlisting>:0
* &lt; 1000
! goodmail@example2.com</programlisting>

    <para>Send all mail sent to <email>alternate@example.com</email>
      into a mailbox called <filename>alternate</filename>:</para>

    <programlisting>:0
* ^TOalternate@example.com
alternate</programlisting>

    <para>Send all mail with a subject of <quote>Spam</quote> to
      <filename>/dev/null</filename>:</para>

    <programlisting>:0
^Subject:.*Spam
/dev/null</programlisting>

    <para>A useful recipe that parses incoming <hostid role="domainname">&os;.org</hostid> mailing lists
      and places each list in its own mailbox:</para>

    <programlisting>:0
* ^Sender:.owner-freebsd-\/[^@]+@FreeBSD.ORG
{
	LISTNAME=${MATCH}
	:0
	* LISTNAME??^\/[^@]+
	FreeBSD-${MATCH}
}</programlisting>
  </sect1>
</chapter>

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