diff --git a/lib/web/auth.js b/lib/web/auth.js
index 5e5b3256..3d5ed208 100644
--- a/lib/web/auth.js
+++ b/lib/web/auth.js
@@ -43,7 +43,7 @@ function handleLogin(req, res) {
         } else {
             var auth = user.name + ":" + user.hash;
             res.cookie("auth", auth, {
-                domain: Config.get("http.root-domain"),
+                domain: "." + Config.get("http.root-domain"),
                 expires: new Date(Date.now() + 7*24*60*60*1000),
                 httpOnly: true
             });