diff --git a/Shorewall/manpages/shorewall-interfaces.xml b/Shorewall/manpages/shorewall-interfaces.xml
index 48bbb9bf5..58361014d 100644
--- a/Shorewall/manpages/shorewall-interfaces.xml
+++ b/Shorewall/manpages/shorewall-interfaces.xml
@@ -70,8 +70,7 @@
           in this column.</para>
 
           <para>If the interface serves multiple zones that will be defined in
-          the <ulink
-          url="shorewall-hosts.html">shorewall-hosts</ulink>(5)
+          the <ulink url="shorewall-hosts.html">shorewall-hosts</ulink>(5)
           file, you should place "-" in this column.</para>
 
           <para>If there are multiple interfaces to the same zone, you must
@@ -109,8 +108,8 @@ loc     eth2            -</programlisting>
           <para>When using Shorewall versions before 4.1.4, care must be
           exercised when using wildcards where there is another zone that uses
           a matching specific interface. See <ulink
-          url="shorewall-nesting.html">shorewall-nesting</ulink>(5)
-          for a discussion of this problem.</para>
+          url="shorewall-nesting.html">shorewall-nesting</ulink>(5) for a
+          discussion of this problem.</para>
 
           <para>Shorewall allows '+' as an interface name, but that usage is
           deprecated. A better approach is to specify
@@ -370,8 +369,7 @@ loc     eth2            -</programlisting>
                 firewall through this interface and whether the source address
                 and/or destination address is to be compared against the
                 ipset-based dynamic blacklist (DYNAMIC_BLACKLIST=ipset... in
-                <ulink
-                url="shorewall.conf.html">shorewall.conf(5)</ulink>).
+                <ulink url="shorewall.conf.html">shorewall.conf(5)</ulink>).
                 The default is determine by the setting of
                 DYNAMIC_BLACKLIST:</para>
 
@@ -459,8 +457,8 @@ loc     eth2            -</programlisting>
 
                   <listitem>
                     <para>the interface is a <ulink
-                    url="../SimpleBridge.html">simple bridge</ulink> with a DHCP
-                    server on one port and DHCP clients on another
+                    url="../SimpleBridge.html">simple bridge</ulink> with a
+                    DHCP server on one port and DHCP clients on another
                     port.</para>
 
                     <note>
@@ -585,8 +583,8 @@ loc     eth2            -</programlisting>
               <listitem>
                 <para>Connection requests from this interface are compared
                 against the contents of <ulink
-                url="shorewall-maclist.html">shorewall-maclist</ulink>(5).
-                If this option is specified, the interface must be an Ethernet
+                url="shorewall-maclist.html">shorewall-maclist</ulink>(5). If
+                this option is specified, the interface must be an Ethernet
                 NIC and must be up before Shorewall is started.</para>
               </listitem>
             </varlistentry>
@@ -650,8 +648,8 @@ loc     eth2            -</programlisting>
 
                 <para>Smurfs will be optionally logged based on the setting of
                 SMURF_LOG_LEVEL in <ulink
-                url="shorewall.conf.html">shorewall.conf</ulink>(5).
-                After logging, the packets are dropped.</para>
+                url="shorewall.conf.html">shorewall.conf</ulink>(5). After
+                logging, the packets are dropped.</para>
               </listitem>
             </varlistentry>
 
@@ -659,6 +657,11 @@ loc     eth2            -</programlisting>
               <term><emphasis role="bold">optional</emphasis></term>
 
               <listitem>
+                <para>This option indicates that the firewall should be able
+                to start, even if the interface is not usable for handling
+                traffic. It allows use of the <command>enable</command> and
+                <command>disable</command> commands on the interface.</para>
+
                 <para>When <option>optional</option> is specified for an
                 interface, Shorewall will be silent when:</para>
 
@@ -674,6 +677,16 @@ loc     eth2            -</programlisting>
                     <para>The first address of the interface cannot be
                     obtained.</para>
                   </listitem>
+
+                  <listitem>
+                    <para>The gateway of the interface can not be obtained
+                    (provider interface).</para>
+                  </listitem>
+
+                  <listitem>
+                    <para>The interface has been disabled using the
+                    <command>disable</command> command.</para>
+                  </listitem>
                 </itemizedlist>
 
                 <para>May not be specified with <emphasis
@@ -826,9 +839,9 @@ loc     eth2            -</programlisting>
 
                 <important>
                   <para>If ROUTE_FILTER=Yes in <ulink
-                  url="shorewall.conf.html">shorewall.conf</ulink>(5),
-                  or if your distribution sets net.ipv4.conf.all.rp_filter=1
-                  in <filename>/etc/sysctl.conf</filename>, then setting
+                  url="shorewall.conf.html">shorewall.conf</ulink>(5), or if
+                  your distribution sets net.ipv4.conf.all.rp_filter=1 in
+                  <filename>/etc/sysctl.conf</filename>, then setting
                   <emphasis role="bold">routefilter</emphasis>=0 in an
                   <replaceable>interface</replaceable> entry will not disable
                   route filtering on that
@@ -848,8 +861,8 @@ loc     eth2            -</programlisting>
                   <itemizedlist>
                     <listitem>
                       <para>If USE_DEFAULT_RT=Yes in <ulink
-                      url="shorewall.conf.html">shorewall.conf</ulink>(5)
-                      and the interface is listed in <ulink
+                      url="shorewall.conf.html">shorewall.conf</ulink>(5) and
+                      the interface is listed in <ulink
                       url="shorewall-providers.html">shorewall-providers</ulink>(5).</para>
                     </listitem>