diff --git a/init.d/sysv/custom.d.examples/10-keenetic-udp-fix b/init.d/sysv/custom.d.examples/10-keenetic-udp-fix
index 554e6fb..f9cab11 100644
--- a/init.d/sysv/custom.d.examples/10-keenetic-udp-fix
+++ b/init.d/sysv/custom.d.examples/10-keenetic-udp-fix
@@ -10,11 +10,13 @@ zapret_custom_firewall()
 
 	local wan wanif rule
 
-	# use IFACE_WAN if defined. if not - search for interfaces with default route.
-	wanif=${IFACE_WAN:-$(sed -nre 's/^([^\t]+)\t00000000\t[0-9A-F]{8}\t[0-9A-F]{4}\t[0-9]+\t[0-9]+\t[0-9]+\t00000000.*$/\1/p' /proc/net/route | sort -u | xargs)}
-	for wan in $wanif; do
-		rule="-o $wan -p udp -m mark --mark $DESYNC_MARK/$DESYNC_MARK"
-		ipt_print_op $1 "$rule" "keenetic udp fix"
-		ipt_add_del $1 POSTROUTING -t nat $rule -j MASQUERADE
-	done
+	[ "$DISABLE_IPV4" = "1" ] || {
+		# use IFACE_WAN if defined. if not - search for interfaces with default route.
+		wanif=${IFACE_WAN:-$(sed -nre 's/^([^\t]+)\t00000000\t[0-9A-F]{8}\t[0-9A-F]{4}\t[0-9]+\t[0-9]+\t[0-9]+\t00000000.*$/\1/p' /proc/net/route | sort -u | xargs)}
+		for wan in $wanif; do
+			rule="-o $wan -p udp -m mark --mark $DESYNC_MARK/$DESYNC_MARK"
+			ipt_print_op $1 "$rule" "keenetic udp fix"
+			ipt_add_del $1 POSTROUTING -t nat $rule -j MASQUERADE
+		done
+	}
 }