diff --git a/.travis.yml b/.travis.yml
index 56ecee8..3fc3c9c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,7 @@ python:
     - 2.6
     - 2.7
 install:
-    - pip install zc.buildout
+    - pip install zc.buildout==2.3.1
     - buildout bootstrap
     - buildout
 script:
diff --git a/buildout.cfg b/buildout.cfg
index efbd4be..3759cd8 100644
--- a/buildout.cfg
+++ b/buildout.cfg
@@ -1,5 +1,6 @@
 [buildout]
 extends = https://raw.githubusercontent.com/zopefoundation/Zope/2.13/version_ranges.cfg
+index = https://pypi.org/simple/
 develop = .
 parts = interpreter test
 versions = versions