diff --git a/xml/fencing.rng b/xml/fencing.rng
index c824987b00..87de5a8b05 100644
--- a/xml/fencing.rng
+++ b/xml/fencing.rng
@@ -1,29 +1,29 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <grammar xmlns="http://relaxng.org/ns/structure/1.0" 
          datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
   <start>
       <ref name="element-stonith"/>
   </start>
 
   <define name="element-stonith">
     <element name="fencing-topology">
       <zeroOrMore>
 	<ref name="element-level"/>
       </zeroOrMore>
     </element>
   </define>
   
   <define name="element-level">
     <element name="fencing-level">
       <attribute name="id"><data type="ID"/></attribute>
       <attribute name="target"><text/></attribute>
       <attribute name="index"><data type="positiveInteger"/></attribute>
       <attribute name="devices">
 	<data type="string">
-          <param name="pattern">([a-zA-Z0-9_.-]+)(,[a-zA-Z0-9_.-]+)*</param>
+          <param name="pattern">([a-zA-Z0-9_\.\-]+)(,[a-zA-Z0-9_\.\-]+)*</param>
 	</data>
       </attribute>
     </element>
   </define>
 
 </grammar>