diff --git a/tox.ini b/tox.ini
index 20a1e73..a9409af 100644
--- a/tox.ini
+++ b/tox.ini
@@ -36,11 +36,8 @@ commands = python setup.py build_sphinx
 commands = python setup.py testr --coverage --testr-args='{posargs}'
 
 [flake8]
-# H305,H307 - fail to detect that oslo.config is an external library
-# H405,E126 - should be fixed
-
 show-source = True
-ignore = H305,H307,H405,E126
+ignore = H405
 exclude=.venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build
 
 [hacking]