diff -rup xen-3.1.0-src.orig/tools/python/xen/xend/server/netif.py xen-3.1.0-src.new/tools/python/xen/xend/server/netif.py
--- xen-3.1.0-src.orig/tools/python/xen/xend/server/netif.py	2007-09-19 14:24:34.000000000 -0400
+++ xen-3.1.0-src.new/tools/python/xen/xend/server/netif.py	2007-09-19 14:25:28.000000000 -0400
@@ -108,17 +108,15 @@ class NetifController(DevController):
         ipaddr  = config.get('ip')
         model   = config.get('model')
 
-        if not typ:
-            typ = xoptions.netback_type
-
         if not mac:
             mac = randomMAC()
 
         devid = self.allocateDeviceID()
 
         back = { 'script' : script,
-                 'mac'    : mac,
-                 'type'   : typ }
+                 'mac'    : mac }
+        if typ:
+            back['type'] = typ
         if ipaddr:
             back['ip'] = ipaddr
         if bridge: