diff --git a/tox.ini b/tox.ini
index 937b93db65c5..616b90c49b81 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 2.0
+minversion = 2.1
 envlist = py{35,27},functional,pep8,pip-missing-reqs
 skipsdist = True
 
@@ -19,7 +19,7 @@ deps = -r{toxinidir}/test-requirements.txt
 commands =
   find . -type f -name "*.pyc" -delete
   rm -Rf .testrepository/times.dbm
-passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY OS_DEBUG GENERATE_HASHES
+passenv = OS_DEBUG GENERATE_HASHES
 # there is also secret magic in subunit-trace which lets you run in a fail only
 # mode. To do this define the TRACE_FAILONLY environmental variable.