diff --git a/Shorewall/lib.base b/Shorewall/lib.base
index 6fdc9a00b..bd9d3d9cf 100644
--- a/Shorewall/lib.base
+++ b/Shorewall/lib.base
@@ -135,6 +135,32 @@ mutex_off()
     rm -f ${LOCKFILE:=${VARDIR}/lock}
 }
 
+#
+# Find the interface with the passed MAC address
+#
+
+find_interface_by_mac() {
+    local mac
+    mac=$1
+    local first
+    local second
+    local rest
+    local dev
+
+    $IP link list | while read first second rest; do
+	case $first in
+	    *:)
+                dev=$second
+		;;
+	    *)
+	        if [ "$second" = $mac ]; then
+		    echo ${dev%:}
+		    return
+		fi
+	esac
+    done
+}
+
 [ -z "$LEFTSHIFT" ] && . ${SHAREDIR}/lib.common
 
 #
diff --git a/Shorewall/lib.common b/Shorewall/lib.common
index ab561b355..353bfa5d2 100644
--- a/Shorewall/lib.common
+++ b/Shorewall/lib.common
@@ -411,32 +411,6 @@ in_network() # $1 = IP address, $2 = CIDR network
     test $(( $(decodeaddr $1) & $netmask)) = $(( $(decodeaddr ${2%/*}) & $netmask ))
 }
 
-#
-# Find the interface with the passed MAC address
-#
-
-find_interface_by_mac() {
-    local mac
-    mac=$1
-    local first
-    local second
-    local rest
-    local dev
-
-    $IP link list | while read first second rest; do
-	case $first in
-	    *:)
-                dev=$second
-		;;
-	    *)
-	        if [ "$second" = $mac ]; then
-		    echo ${dev%:}
-		    return
-		fi
-	esac
-    done
-}
-
 #
 # Find interface address--returns the first IP address assigned to the passed
 # device