  <varlistentry>
  <term><emphasis remap='B'>sha2-truncbug</emphasis></term>
  <listitem>
<para>The default ESP hash truncation for sha2_256 is 128 bits. Some
IPsec implementations (Linux before 2.6.33, some Cisco (2811?) routers)
implement the draft version which stated 96 bits. If a draft implementation
communicates with an RFC implementation, both ends will reject encrypted
packets from each other.</para>

<para>This option enables using the draft 96 bits version to interop
with those implementations.  Currently the accepted values are
<emphasis remap='B'>no</emphasis>, (the default) signifying default RFC
truncation of 128 bits, or <emphasis remap='B'>yes</emphasis>, signifying
the draft 96 bits truncation.  </para>
<para>Another workaround is to switch from sha2_256 to sha2_128 or sha2_512.</para>
  </listitem>
  </varlistentry>

