diff --git a/Shorewall/Perl/Shorewall/Nat.pm b/Shorewall/Perl/Shorewall/Nat.pm
index e9ce87f63..4e3366f54 100644
--- a/Shorewall/Perl/Shorewall/Nat.pm
+++ b/Shorewall/Perl/Shorewall/Nat.pm
@@ -459,7 +459,9 @@ sub do_one_nat( $$$$$ )
 
     fatal_error "Unknown interface ($interface)" unless my $interfaceref = known_interface( $interface );
 
-    unless ( $interfaceref->{root} ) {
+    if ( $interfaceref->{root} ) {
+	$interface = $interfaceref->{name} if $interface eq $interfaceref->{physical};
+    } else {
 	$rulein  = match_source_dev $interface;
 	$ruleout = match_dest_dev $interface;
 	$interface = $interfaceref->{name};
@@ -561,7 +563,9 @@ sub setup_netmap() {
 		    $net1 = validate_net $net1, 0;
 		    $net2 = validate_net $net2, 0;
 
-		    unless ( $interfaceref->{root} ) {
+		    if ( $interfaceref->{root} ) {
+			$interface = $interfaceref->{name} if $interface eq $interfaceref->{physical};
+		    } else {
 			@rulein  = imatch_source_dev( $interface );
 			@ruleout = imatch_dest_dev( $interface );
 			$interface = $interfaceref->{name};
diff --git a/Shorewall/manpages/shorewall.conf.xml b/Shorewall/manpages/shorewall.conf.xml
index 3621f6b40..b8ce10623 100644
--- a/Shorewall/manpages/shorewall.conf.xml
+++ b/Shorewall/manpages/shorewall.conf.xml
@@ -1648,7 +1648,7 @@ LOG:info:,bar                        net                    fw</programlisting>
 
       <varlistentry>
         <term><emphasis
-        role="bold">MODULESDIR=</emphasis>[<emphasis>pathname</emphasis>[<emphasis
+        role="bold">MODULESDIR=</emphasis>[[+]<emphasis>pathname</emphasis>[<emphasis
         role="bold">:</emphasis><emphasis>pathname</emphasis>]...]</term>
 
         <listitem>
@@ -1659,6 +1659,10 @@ LOG:info:,bar                        net                    fw</programlisting>
           where <emphasis role="bold">uname</emphasis> holds the output of
           '<command>uname -r</command>' and <emphasis
           role="bold">g_family</emphasis> holds '4'.</para>
+
+          <para>The option plus sign ('+') was added in Shorewall 5.0.3 and
+          causes the listed pathnames to be appended to the default list
+          above.</para>
         </listitem>
       </varlistentry>
 
diff --git a/Shorewall6/manpages/shorewall6.conf.xml b/Shorewall6/manpages/shorewall6.conf.xml
index 168b40edd..e643d5050 100644
--- a/Shorewall6/manpages/shorewall6.conf.xml
+++ b/Shorewall6/manpages/shorewall6.conf.xml
@@ -1436,7 +1436,7 @@ LOG:info:,bar                        net                    fw</programlisting>
 
       <varlistentry>
         <term><emphasis
-        role="bold">MODULESDIR=</emphasis>[<emphasis>pathname</emphasis>[<emphasis
+        role="bold">MODULESDIR=</emphasis>[[+]<emphasis>pathname</emphasis>[<emphasis
         role="bold">:</emphasis><emphasis>pathname</emphasis>]...]</term>
 
         <listitem>
@@ -1447,6 +1447,10 @@ LOG:info:,bar                        net                    fw</programlisting>
           where <emphasis role="bold">uname</emphasis> holds the output of
           '<command>uname -r</command>' and <emphasis
           role="bold">g_family</emphasis> holds '6'.</para>
+
+          <para>The option plus sign ('+') was added in Shorewall 5.0.3 and
+          causes the listed pathnames to be appended to the default list
+          above.</para>
         </listitem>
       </varlistentry>