diff --git a/luci-app-firewall/htdocs/luci-static/resources/view/firewall/zones.js b/luci-app-firewall/htdocs/luci-static/resources/view/firewall/zones.js
index 8393c591..b1a5d788 100644
--- a/luci-app-firewall/htdocs/luci-static/resources/view/firewall/zones.js
+++ b/luci-app-firewall/htdocs/luci-static/resources/view/firewall/zones.js
@@ -73,6 +73,7 @@ return view.extend({
 			addTCPCCAOption();
 			if (fw4)
 				o = s.option(form.Flag, 'fullcone6', _('Enable FullCone NAT6'));
+				o.depends('fullcone', '1');
 		}
 		else {
 			addTCPCCAOption();