diff --git a/requirements.txt b/requirements.txt
index b2d4bb4d..ff0845d6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -22,6 +22,12 @@ chardet>2.3.0
 wtforms~=3.0
 jsonpath-ng~=1.5.3
 
+
+# dnspython 2.3.0 is not compatible with eventlet
+# * https://github.com/eventlet/eventlet/issues/781
+# * https://datastax-oss.atlassian.net/browse/PYTHON-1320
+dnspython<2.3.0
+
 # jq not available on Windows so must be installed manually
 
 # Notification library