diff --git a/packages/next/src/experimental/testmode/proxy/server.ts b/packages/next/src/experimental/testmode/proxy/server.ts
index 6139d44ffc94e..70c6badf867ab 100644
--- a/packages/next/src/experimental/testmode/proxy/server.ts
+++ b/packages/next/src/experimental/testmode/proxy/server.ts
@@ -58,7 +58,7 @@ export async function createProxyServer({
   })
 
   await new Promise((resolve) => {
-    server.listen(0, 'localhost', () => {
+    server.listen(0, '::', () => {
       resolve(undefined)
     })
   })