diff --git a/oslo_serialization/jsonutils.py b/oslo_serialization/jsonutils.py
index 7637d5a..cbffc90 100644
--- a/oslo_serialization/jsonutils.py
+++ b/oslo_serialization/jsonutils.py
@@ -191,14 +191,16 @@ def dump(obj, fp, *args, **kwargs):
 
     :param obj: object to be serialized
     :param fp: a ``.write()``-supporting file-like object
+    :param default: function that returns a serializable version of an object
     :param args: extra arguments, please see documentation \
     of `json.dump <https://docs.python.org/2/library/json.html#basic-usage>`_
     :param kwargs: extra named parameters, please see documentation \
     of `json.dump <https://docs.python.org/2/library/json.html#basic-usage>`_
     """
+    default = kwargs.get('default', to_primitive)
     if is_simplejson:
         kwargs['namedtuple_as_object'] = False
-    return json.dump(obj, fp, *args, **kwargs)
+    return json.dump(obj, fp, default=default, *args, **kwargs)
 
 
 def loads(s, encoding='utf-8', **kwargs):
diff --git a/tests/test_jsonutils.py b/tests/test_jsonutils.py
index a1e1408..5ab465c 100644
--- a/tests/test_jsonutils.py
+++ b/tests/test_jsonutils.py
@@ -262,6 +262,17 @@ class ToPrimitiveTestCase(test_base.BaseTestCase):
         ret = jsonutils.to_primitive(thing)
         self.assertEqual({'ip_addr': '1.2.3.4'}, ret)
 
+    def test_dumps_ipaddr(self):
+        thing = {'ip_addr': netaddr.IPAddress('1.2.3.4')}
+        ret = jsonutils.dumps(thing)
+        self.assertEqual('{"ip_addr": "1.2.3.4"}', ret)
+
+    def test_dump_ipaddr(self):
+        thing = {'ip_addr': netaddr.IPAddress('1.2.3.4')}
+        fp = six.StringIO()
+        jsonutils.dump(thing, fp)
+        self.assertEqual('{"ip_addr": "1.2.3.4"}', fp.getvalue())
+
     def test_message_with_param(self):
         msg = self.trans_fixture.lazy('A message with param: %s')
         msg = msg % 'test_domain'