  <varlistentry>
  <term><emphasis remap='B'>auth</emphasis></term>
  <listitem>
<para>whether authentication should be done as part of
ESP encryption, or separately using the AH protocol;
acceptable values are
<emphasis remap='B'>esp</emphasis>
(the default) and
<emphasis remap='B'>ah</emphasis>.</para>
  </listitem>
  </varlistentry>
