diff --git a/qubes/firewall.py b/qubes/firewall.py
index fed1358b..2a278a92 100644
--- a/qubes/firewall.py
+++ b/qubes/firewall.py
@@ -388,14 +388,14 @@ class Rule(qubes.PropertyHolder):
     @qubes.events.handler('property-set:forwardtype')
     def on_set_forwardtype(self, event, name, newvalue, oldvalue=None):
         # pylint: disable=unused-argument
-        if self.action is not 'forward':
+        if self.action != 'forward':
             raise ValueError(
                 'forwardtype valid only for forward action')
 
     @qubes.events.handler('property-set:srcports')
     def on_set_srcports(self, event, name, newvalue, oldvalue=None):
         # pylint: disable=unused-argument
-        if self.action is not 'forward':
+        if self.action != 'forward':
             raise ValueError(
                 'srcports valid only for forward action')