diff --git a/lib/neutron-legacy b/lib/neutron-legacy
index f83492b..f4e577d 100644
--- a/lib/neutron-legacy
+++ b/lib/neutron-legacy
@@ -203,7 +203,7 @@
 # agent, as described below.
 #
 # Example: ``PHYSICAL_NETWORK=default``
-PHYSICAL_NETWORK=${PHYSICAL_NETWORK:-public}
+PHYSICAL_NETWORK=${PHYSICAL_NETWORK:-}
 
 # With the openvswitch agent, if using VLANs for tenant networks,
 # or if using flat or VLAN provider networks, set in ``localrc`` to
@@ -213,7 +213,7 @@
 # port for external connectivity.
 #
 # Example: ``OVS_PHYSICAL_BRIDGE=br-eth1``
-OVS_PHYSICAL_BRIDGE=${OVS_PHYSICAL_BRIDGE:-br-ex}
+OVS_PHYSICAL_BRIDGE=${OVS_PHYSICAL_BRIDGE:-}
 
 # With the linuxbridge agent, if using VLANs for tenant networks,
 # or if using flat or VLAN provider networks, set in ``localrc`` to