diff --git a/quantum/db/l3_db.py b/quantum/db/l3_db.py
index 1c6707c2c6..6585733adc 100644
--- a/quantum/db/l3_db.py
+++ b/quantum/db/l3_db.py
@@ -709,7 +709,7 @@ class L3_NAT_db_mixin(l3.RouterPluginBase):
                 network_id=net_id).delete()
 
     def _filter_nets_l3(self, context, nets, filters):
-        vals = filters.get('router:external', [])
+        vals = filters and filters.get('router:external', [])
         if not vals:
             return nets
 
diff --git a/quantum/tests/unit/test_l3_plugin.py b/quantum/tests/unit/test_l3_plugin.py
index 741a96bea2..29ca27d9f3 100644
--- a/quantum/tests/unit/test_l3_plugin.py
+++ b/quantum/tests/unit/test_l3_plugin.py
@@ -892,6 +892,12 @@ class L3NatDBTestCase(test_db_plugin.QuantumDbPluginV2TestCase):
                                   query_params="%s=False" % l3.EXTERNAL)
                 self.assertEquals(len(body['networks']), 1)
 
+    def test_get_network_succeeds_without_filter(self):
+        plugin = manager.QuantumManager.get_plugin()
+        ctx = context.Context(None, None, is_admin=True)
+        result = plugin.get_networks(ctx, filters=None)
+        self.assertEqual(result, [])
+
     def test_network_filter_hook_admin_context(self):
         plugin = manager.QuantumManager.get_plugin()
         ctx = context.Context(None, None, is_admin=True)