diff --git a/Dockerfile b/Dockerfile
index 20bd885..0ccb968 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -31,6 +31,10 @@ ENV PORT=3132 \
     SITESPEED_BIN=/usr/local/lib/node_modules/sitespeed.io/bin/sitespeed.js \
     NODE_ENV=production
 
-EXPOSE 3000
+EXPOSE 3132
 
-CMD ["node", "app.js"]
+# Override the base image's ENTRYPOINT (which is "sitespeed.io") so that
+# Docker doesn't prepend it to our CMD, causing sitespeed.io to treat
+# "node" as a URL to test.
+ENTRYPOINT ["node"]
+CMD ["app.js"]