Index: smtp/src/main/java/org/apache/james/protocols/smtp/core/fastfail/DNSRBLHandler.java
===================================================================
--- smtp/src/main/java/org/apache/james/protocols/smtp/core/fastfail/DNSRBLHandler.java	(revision 1074454)
+++ smtp/src/main/java/org/apache/james/protocols/smtp/core/fastfail/DNSRBLHandler.java	(working copy)
@@ -81,7 +81,7 @@
      * @param whitelist The array which contains the whitelist
      */
     public void setWhitelist(String[] whitelist) {
-        this.whitelist = whitelist;
+        this.whitelist = whitelist.clone();
     }
     
     /**
@@ -90,7 +90,7 @@
      * @param blacklist The array which contains the blacklist
      */
     public void setBlacklist(String[] blacklist) {
-        this.blacklist = blacklist;
+        this.blacklist = blacklist.clone();
     }
 
     /**