diff --git a/packages/@vue/cli-service/lib/util/prepareProxy.js b/packages/@vue/cli-service/lib/util/prepareProxy.js
index 0b525d7487..1c99f31d60 100644
--- a/packages/@vue/cli-service/lib/util/prepareProxy.js
+++ b/packages/@vue/cli-service/lib/util/prepareProxy.js
@@ -17,7 +17,10 @@ const defaultConfig = {
   secure: false,
   changeOrigin: true,
   ws: true,
-  xfwd: true
+  xfwd: true,
+  headers: {
+    Connection: 'keep-alive'
+  }
 }
 
 module.exports = function prepareProxy (proxy, appPublicFolder) {