diff --git a/Dynamic-filtering:-default-deny:-useful-rulesets.md b/Dynamic-filtering:-default-deny:-useful-rulesets.md
index 907b71e..26f07d2 100644
--- a/Dynamic-filtering:-default-deny:-useful-rulesets.md
+++ b/Dynamic-filtering:-default-deny:-useful-rulesets.md
@@ -8,6 +8,9 @@ Reminder: the `noop` rule action means that network requests will not be filtere
 
     # Global
 
+    # exception for enabling firefox sync
+    * services.mozilla.com * noop
+
     # This one is useful if you want to keep the ability to translate
     # any web page using the contextual menu in Chromium:
     * translate.googleapis.com * noop