diff --git a/src/etc/rc.filter_configure_sync b/src/etc/rc.filter_configure_sync
index 595a138ee..fbd2df22a 100755
--- a/src/etc/rc.filter_configure_sync
+++ b/src/etc/rc.filter_configure_sync
@@ -33,5 +33,6 @@ require_once("util.inc");
 require_once("filter.inc");
 require_once("ipsec.inc");
 require_once("vpn.inc");
+require_once("system.inc");
 
 filter_configure_sync();