diff --git a/UPDATING b/UPDATING
index cdea211db962..acf07dc9bf38 100644
--- a/UPDATING
+++ b/UPDATING
@@ -31,6 +31,14 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 12.x IS SLOW:
 	disable the most expensive debugging functionality run
 	"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20160818:
+	The UDP receive code has been updated to only treat incoming UDP
+	packets that were addressed to an L2 broadcast address as L3
+	broadcast packets.  It is not expected that this will affect any
+	standards-conforming UDP application.  The new behaviour can be
+	disabled by setting the sysctl net.inet.udp.require_l2_bcast to
+	0.
+
 20160818:
 	Remove the openbsd_poll system call.
         __FreeBSD_version has been bumped because of this.
diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
index 173c44ce2a06..f0837cfe8cac 100644
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -126,6 +126,11 @@ SYSCTL_INT(_net_inet_udp, OID_AUTO, blackhole, CTLFLAG_VNET | CTLFLAG_RW,
     &VNET_NAME(udp_blackhole), 0,
     "Do not send port unreachables for refused connects");
 
+static VNET_DEFINE(int, udp_require_l2_bcast) = 1;
+SYSCTL_INT(_net_inet_udp, OID_AUTO, require_l2_bcast, CTLFLAG_VNET | CTLFLAG_RW,
+    &VNET_NAME(udp_require_l2_bcast), 0,
+    "Only treat packets sent to an L2 broadcast address as broadcast packets");
+
 u_long	udp_sendspace = 9216;		/* really max datagram size */
 SYSCTL_ULONG(_net_inet_udp, UDPCTL_MAXDGRAM, maxdgram, CTLFLAG_RW,
     &udp_sendspace, 0, "Maximum outgoing UDP datagram size");
@@ -523,7 +528,8 @@ udp_input(struct mbuf **mp, int *offp, int proto)
 
 	pcbinfo = udp_get_inpcbinfo(proto);
 	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
-	    in_broadcast(ip->ip_dst, ifp)) {
+	    ((!VNET_NAME(udp_require_l2_bcast) || m->m_flags & M_BCAST) &&
+	    in_broadcast(ip->ip_dst, ifp))) {
 		struct inpcb *last;
 		struct inpcbhead *pcblist;
 		struct ip_moptions *imo;