diff --git a/.travis.yml b/.travis.yml
index 2ec3e3b5..13b9a417 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,7 +20,7 @@ install:
   - pip install -r requirements.txt
   - if [[ $TRAVIS_PYTHON_VERSION != pypy* ]]; then pip install coveralls; fi
 env:
-  - HTTPBIN=httpbin.bemisc.com
+  - PIP_TRUSTED_HOST="pypi.python.org pypi.org files.pythonhosted.org" HTTPBIN=httpbin.bemisc.com
 script: if [[ $TRAVIS_PYTHON_VERSION != pypy* ]]; then coverage run --source=netius setup.py test; else python setup.py test; fi
 after_success: if [[ $TRAVIS_PYTHON_VERSION != pypy* ]]; then coveralls; fi
 notifications: