diff --git a/docs/MultiISP.xml b/docs/MultiISP.xml
index d5a5e3883..bb58bd940 100644
--- a/docs/MultiISP.xml
+++ b/docs/MultiISP.xml
@@ -360,6 +360,16 @@
                   applied.</para>
                 </listitem>
               </varlistentry>
+
+              <varlistentry>
+                <term>optional (added in Shorewall 3.2.2)</term>
+
+                <listitem>
+                  <para>Shorewall will determine of this interface is up and
+                  has a configured IPv4 address. If it is not, a warning is
+                  issued and this provider is not configured.</para>
+                </listitem>
+              </varlistentry>
             </variablelist>
           </listitem>
         </varlistentry>