add note about turning off nat-net
diff --git a/xos/configurations/cord/README-VTN.md b/xos/configurations/cord/README-VTN.md
index b1a0374..9e2f638 100644
--- a/xos/configurations/cord/README-VTN.md
+++ b/xos/configurations/cord/README-VTN.md
@@ -38,7 +38,6 @@
     emacs /usr/local/lib/python2.7/dist-packages/networking_onos/plugins/ml2/driver.py
         hard-code self.onos_path and self.onos_auth
     
-
 Compute node that has the ONOS Container
 
     # we need NAT rule so the neutron vtn plugin can talk to onos
@@ -61,3 +60,4 @@
 
 Problems:
 * If you have more than one compute node, then the node that isn't running ONOS VTN will report as incomplete in VTN. This is because the openvswitch is trying to contact VTN on 172.17.0.2:6653. 
+* VTN doesn't like the nat-net network that XOS creates by default. Go into model_policies/model_policy_Slice.py and disable automatic creation of nat-net.