diff --git a/kernel-module/xt_RTPENGINE.c b/kernel-module/xt_RTPENGINE.c
index 2108a1efa..e7352d336 100644
--- a/kernel-module/xt_RTPENGINE.c
+++ b/kernel-module/xt_RTPENGINE.c
@@ -3680,7 +3680,7 @@ static unsigned int rtpengine46(struct sk_buff *skb, struct rtpengine_table *t,
 	u32 = (void *) skb->data;
 	if (u32[1] != htonl(0x2112A442UL)) /* magic cookie */
 		goto not_stun;
-	if ((u32[0] & htonl(0xb0000003UL))) /* zero bits required by rfc */
+	if ((u32[0] & htonl(0xc0000003UL))) /* zero bits required by rfc */
 		goto not_stun;
 	u32 = (void *) &skb->data[datalen - 8];
 	if (u32[0] != htonl(0x80280004UL)) /* required fingerprint attribute */