shadow/man/login.access.5.xml

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<refentry id='login.access.5'>
  <!-- $Id$ -->
  <refentryinfo>
    <author>
      <firstname>Marek</firstname>
      <surname>Michałkiewicz</surname>
      <contrib>Creation, 1996</contrib>
    </author>
    <author>
      <firstname>Thomas</firstname>
      <surname>Kłoczko</surname>
      <email>kloczek@pld.org.pl</email>
      <contrib>shadow-utils maintainer, 2000 - 2007</contrib>
    </author>
    <author>
      <firstname>Nicolas</firstname>
      <surname>François</surname>
      <email>nicolas.francois@centraliens.net</email>
      <contrib>shadow-utils maintainer, 2007 - now</contrib>
    </author>
  </refentryinfo>
  <refmeta>
    <refentrytitle>login.access</refentrytitle>
    <manvolnum>5</manvolnum>
    <refmiscinfo class="sectdesc">File Formats and Conversions</refmiscinfo>
    <refmiscinfo class="source">shadow-utils</refmiscinfo>
    <refmiscinfo class="version">&SHADOW_UTILS_VERSION;</refmiscinfo>
  </refmeta>
  <refnamediv id='name'>
    <refname>login.access</refname>
    <refpurpose>login access control table</refpurpose>
  </refnamediv>

  <refsect1 id='description'>
    <title>DESCRIPTION</title>
    <para>
      The <emphasis remap='I'>login.access</emphasis> file specifies (user,
      host) combinations and/or (user, tty) combinations for which a login
      will be either accepted or refused.
    </para>

    <para>
      When someone logs in, the <emphasis remap='I'>login.access</emphasis>
      is scanned for the first entry that matches the (user, host)
      combination, or, in case of non-networked logins, the first entry that
      matches the (user, tty) combination. The permissions field of that
      table entry determines whether the login will be accepted or refused.
    </para>

    <para>
      Each line of the login access control table has three fields separated
      by a ":" character:
    </para>

    <para>
      <emphasis remap='I'>permission</emphasis>:<emphasis remap='I'>users</emphasis>:<emphasis remap='I'>origins</emphasis>
    </para>

    <para>
      The first field should be a "<emphasis>+</emphasis>" (access granted)
      or "<emphasis>-</emphasis>" (access denied) character. The second
      field should be a list of one or more login names, group names, or
      <emphasis>ALL</emphasis> (always matches). The third field should be a
      list of one or more tty names (for non-networked logins), host names,
      domain names (begin with "<literal>.</literal>"), host addresses,
      internet network numbers (end with "<literal>.</literal>"),
      <emphasis>ALL</emphasis> (always matches) or
      <emphasis>LOCAL</emphasis> (matches any string that does not contain a
      "<literal>.</literal>" character). If you run NIS you can use
      @netgroupname in host or user patterns.
    </para>

    <para>
      The <emphasis>EXCEPT</emphasis> operator makes it possible to write
      very compact rules.
    </para>

    <para>
      The group file is searched only when a name does not match that of the
      logged-in user. Only groups are matched in which users are explicitly
      listed: the program does not look at a user's primary group id value.
    </para>
  </refsect1>

  <refsect1 id='files'>
    <title>FILES</title>
    <variablelist>
      <varlistentry>
	<term><filename>/etc/login.defs</filename></term>
	<listitem>
	  <para>Shadow password suite configuration.</para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id='see_also'>
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
	<refentrytitle>login</refentrytitle><manvolnum>1</manvolnum>
      </citerefentry>.
    </para>
  </refsect1>
</refentry>