diff --git a/doc/source/getting-started.rst b/doc/source/getting-started.rst
index 54ee7b9b..3c2c775d 100644
--- a/doc/source/getting-started.rst
+++ b/doc/source/getting-started.rst
@@ -241,7 +241,7 @@ To build the image from behind a proxy, you can:
 
     export http_proxy=...
     export no_proxy=...
-    docker build --build-arg http_proxy=$http_proxy --build-arg https_proxy=$http_proxy --build-arg no_proxy=$no_proxy  -t promenade:local .
+    docker build --build-arg http_proxy=$http_proxy --build-arg https_proxy=$http_proxy --build-arg no_proxy=$no_proxy -t promenade:local .
 
 
 For convenience, there is a script which builds an image from the current code,
diff --git a/tox.ini b/tox.ini
index be59f95a..d0a2898c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,6 +3,7 @@ envlist = pep8,py35,bandit,docs
 
 [testenv]
 basepython=python3
+passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 
 [testenv:py35]
 setenv =