diff --git a/unit_tests/charm_tests/test_utils.py b/unit_tests/charm_tests/test_utils.py
index a415360..280e2e2 100644
--- a/unit_tests/charm_tests/test_utils.py
+++ b/unit_tests/charm_tests/test_utils.py
@@ -30,15 +30,3 @@ class TestOpenStackBaseTest(unittest.TestCase):
 
         MyTestClass.setUpClass('foo', 'bar')
         _setUpClass.assert_called_with('foo', 'bar')
-
-
-class TestUtils(unittest.TestCase):
-
-    def test_format_addr(self):
-        self.assertEquals('1.2.3.4', test_utils.format_addr('1.2.3.4'))
-        self.assertEquals(
-            '[2001:db8::42]', test_utils.format_addr('2001:db8::42'))
-        with self.assertRaises(ValueError):
-            test_utils.format_addr('999.999.999.999')
-        with self.assertRaises(ValueError):
-            test_utils.format_addr('2001:db8::g')
diff --git a/zaza/openstack/charm_tests/test_utils.py b/zaza/openstack/charm_tests/test_utils.py
index 83595b0..2994629 100644
--- a/zaza/openstack/charm_tests/test_utils.py
+++ b/zaza/openstack/charm_tests/test_utils.py
@@ -14,7 +14,6 @@
 """Module containing base class for implementing charm tests."""
 import contextlib
 import logging
-import ipaddress
 import subprocess
 import tenacity
 import unittest
@@ -541,20 +540,3 @@ class OpenStackBaseTest(BaseCharmTest):
         instance_2 = self.retrieve_guest(
             '{}-ins-1'.format(self.RESOURCE_PREFIX))
         return instance_1, instance_2
-
-
-def format_addr(addr):
-    """Validate and format IP address.
-
-    :param addr: IPv6 or IPv4 address
-    :type addr: str
-    :returns: Address string, optionally encapsulated in brackets([])
-    :rtype: str
-    :raises: ValueError
-    """
-    ipaddr = ipaddress.ip_address(addr)
-    if isinstance(ipaddr, ipaddress.IPv6Address):
-        fmt = '[{}]'
-    else:
-        fmt = '{}'
-    return fmt.format(ipaddr)
diff --git a/zaza/openstack/charm_tests/vault/utils.py b/zaza/openstack/charm_tests/vault/utils.py
index a708d78..9814243 100644
--- a/zaza/openstack/charm_tests/vault/utils.py
+++ b/zaza/openstack/charm_tests/vault/utils.py
@@ -27,7 +27,7 @@ import yaml
 import collections
 
 import zaza.model
-import zaza.openstack.charm_tests.test_utils as test_utils
+import zaza.utilities.networking as network_utils
 
 AUTH_FILE = "vault_tests.yaml"
 CharmVaultClient = collections.namedtuple(
@@ -102,7 +102,7 @@ def get_unit_api_url(ip):
     transport = 'http'
     if vault_config['ssl-cert']['value']:
         transport = 'https'
-    return '{}://{}:8200'.format(transport, test_utils.format_addr(ip))
+    return '{}://{}:8200'.format(transport, network_utils.format_addr(ip))
 
 
 def get_hvac_client(vault_url, cacert=None):
diff --git a/zaza/openstack/utilities/openstack.py b/zaza/openstack/utilities/openstack.py
index 14c708c..34d7e7b 100644
--- a/zaza/openstack/utilities/openstack.py
+++ b/zaza/openstack/utilities/openstack.py
@@ -68,6 +68,8 @@ from zaza.openstack.utilities import (
     exceptions,
     generic as generic_utils,
 )
+import zaza.utilities.networking as network_utils
+
 
 CIRROS_RELEASE_URL = 'http://download.cirros-cloud.net/version/released'
 CIRROS_IMAGE_URL = 'http://download.cirros-cloud.net'
@@ -1704,6 +1706,7 @@ def get_overcloud_auth(address=None, model_name=None):
 
     if not address:
         address = get_keystone_ip(model_name=model_name)
+    address = network_utils.format_addr(address)
 
     password = juju_utils.leader_get(
         'keystone',