diff --git a/firefox/user.js b/firefox/user.js
index 04f82ff..00bb9c1 100755
--- a/firefox/user.js
+++ b/firefox/user.js
@@ -124,8 +124,7 @@ user_pref("media.video_stats.enabled", false);
 user_pref("media.webspeech.synth.enabled", false);
 user_pref("network.allow-experiments", false);
 user_pref("network.dns.disablePrefetch", true);
-// still allow IPv6
-//user_pref("network.dns.disableIPv6", true);
+user_pref("network.dns.disableIPv6", true);
 user_pref("network.captive-portal-service.enabled", false);
 user_pref("network.connectivity-service.enabled", false);
 user_pref("network.http.altsvc.enabled", false);