diff --git a/circle.yml b/circle.yml
index ab379f253..ac8837645 100644
--- a/circle.yml
+++ b/circle.yml
@@ -19,6 +19,8 @@ dependencies:
     - cd testapp && npm update
     - npm start:
           background: true
+    - sudo tcpdump -i lo 'tcp && dst localhost' -w $CIRCLE_ARTIFACTS/localdump.pcap:
+          background: true
 
 test:
   override: