diff --git a/lib/tempest b/lib/tempest
index cce541cdf0..d4d8cf25df 100644
--- a/lib/tempest
+++ b/lib/tempest
@@ -238,7 +238,10 @@ function configure_tempest {
 
     ssh_connect_method=${TEMPEST_SSH_CONNECT_METHOD:-$ssh_connect_method}
 
-    if is_service_enabled q-l3; then
+    # the public network (for floating ip access) is only available
+    # if the extension is enabled.
+    EXTERNAL_NETWORK_EXT=$(neutron ext-list | grep 'external-net' | get_field 1)
+    if [[ -n $EXTERNAL_NETWORK_EXT ]]; then
         public_network_id=$(neutron net-list | grep $PUBLIC_NETWORK_NAME | \
             awk '{print $2}')
     fi