diff --git a/crans_utils.py b/crans_utils.py
index b4b498c..33c5620 100644
--- a/crans_utils.py
+++ b/crans_utils.py
@@ -41,6 +41,12 @@ def ip_of_mid(mid):
             break
     else:
         raise ValueError("Mid dans aucune plage: %d" % mid)
+    
+    if net == 'special':
+        try:
+            return netaddr.IPAddress(config.mid_machines_speciales[mid])
+        except KeyError:
+            return ValueError(u"Machine speciale inconnue: %d" % mid)
 
     return netaddr.IPAddress(netaddr.IPNetwork(config.NETs[net][0]).first + mid - plage[0])