diff --git a/conntrackt/views.py b/conntrackt/views.py
--- a/conntrackt/views.py
+++ b/conntrackt/views.py
@@ -203,13 +203,10 @@ def project_iptables(request, project_id
     if location_id:
         location = get_object_or_404(Location, pk=location_id)
         entities = project.entity_set.filter(location=location)
-        filename = '%s_%s-iptables.zip' % (project.name, location.name)
+        filename = '%s-%s-iptables.zip' % (project.name.lower().replace(" ", "_"), location.name.lower().replace(" ", "_"))
     else:
         entities = project.entity_set.all()
-        filename = '%s-iptables.zip' % (project.name)
-
-    # Lower-case the filename, and replace spaces with underscores (_).
-    filename = filename.lower().replace(" ", "_")
+        filename = '%s-iptables.zip' % (project.name.lower().replace(" ", "_"))
 
     # Render iptables rules for each entity, placing them in the ZIP archive.
     for entity in entities: