diff --git a/congress_tempest_plugin/tests/scenario/manager.py b/congress_tempest_plugin/tests/scenario/manager.py
index a2ee645..fed9c36 100644
--- a/congress_tempest_plugin/tests/scenario/manager.py
+++ b/congress_tempest_plugin/tests/scenario/manager.py
@@ -569,8 +569,13 @@ class NetworkScenarioTest(ScenarioTest):
         return subnet
 
     def _get_server_port_id_and_ip4(self, server, ip_addr=None):
-        ports = self.os_admin.ports_client.list_ports(
-            device_id=server['id'], fixed_ip=ip_addr)['ports']
+        if ip_addr:
+            ports = self.os_admin.ports_client.list_ports(
+                device_id=server['id'],
+                fixed_ips='ip_address=%s' % ip_addr)['ports']
+        else:
+            ports = self.os_admin.ports_client.list_ports(
+                device_id=server['id'])['ports']
         # A port can have more than one IP address in some cases.
         # If the network is dual-stack (IPv4 + IPv6), this port is associated
         # with 2 subnets