--- xen-network-common.sh	2008-07-16 20:02:49.000000000 -0400
+++ xen-network-common.sh	2008-07-16 20:04:28.000000000 -0400
@@ -61,6 +61,12 @@ else
   {
     true
   }
+  # do not call ifdown directly
+  ifdown()  {
+    ip addr flush $1
+    ip link set $1 down
+    true
+  }
 fi