<listitem>
<para>
An optional base DN, search scope and LDAP filter
to restrict LDAP searches for this attribute type.
</para>
<para>
syntax:
<programlisting>
search_base[?scope?[filter][?search_base?scope?[filter]]*]
</programlisting>
</para>
<para>
The scope can be one of "base", "onelevel" or "subtree". The
scope functions as specified in section 4.5.1.2 of
</para>
<para>
The filter must be a valid LDAP search
filter as specified by
</para>
<para>
For examples of this syntax, please refer to the
<quote>ldap_search_base</quote> examples section.
</para>
<para>
Default: the value of
<emphasis>ldap_search_base</emphasis>
</para>
<para>
Please note that specifying scope or filter is not supported for
searches against an Active Directory Server that might yield a
large number of results and trigger the Range Retrieval extension
in the response.
</para>
</listitem>