diff --git a/tempest/api/compute/admin/test_networks.py b/tempest/api/compute/admin/test_networks.py
index e5c8790..8504840 100644
--- a/tempest/api/compute/admin/test_networks.py
+++ b/tempest/api/compute/admin/test_networks.py
@@ -42,8 +42,12 @@
                              "{0} networks with label {1}".format(
                                  len(configured_network),
                                  CONF.compute.fixed_network_name))
+        elif CONF.network.public_network_id:
+            configured_network = [x for x in networks if x['id'] ==
+                                  CONF.network.public_network_id]
         else:
-            configured_network = networks
+            raise self.skipException(
+                "Environment has no known-for-sure existing network.")
         configured_network = configured_network[0]
         network = (self.client.show_network(configured_network['id'])
                    ['network'])