diff --git a/l2tpns.c b/l2tpns.c
index 66f0214..9a8fd4d 100644
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4205,7 +4205,7 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr, uint16_t indexu
 				t, ns, tunnel[t].nr);
 
 			if (tunnel[t].state == TUNNELOPEN
-				&& ns - tunnel[t].nr <= 10 && len <= MAXCONTROL)
+				&& ns - tunnel[t].nr <= CONTROLWIN && len <= MAXCONTROL)
 			{
 				// Not too big and not too new
 				controlt **curp;