Index: sys/netinet/tcp_usrreq.c
===================================================================
--- sys/netinet/tcp_usrreq.c
+++ sys/netinet/tcp_usrreq.c
@@ -321,8 +321,15 @@
 	struct sockaddr_in *sinp;
 
 	sinp = (struct sockaddr_in *)nam;
-	if (nam->sa_family != AF_INET)
-		return (EAFNOSUPPORT);
+	if (nam->sa_family != AF_INET) {
+		/*
+		 * Preserve compatibility with old programs.
+		 */
+		if (nam->sa_family != AF_UNSPEC ||
+		    sinp->sin_addr.s_addr != INADDR_ANY)
+			return (EAFNOSUPPORT);
+		nam->sa_family = AF_INET;
+	}
 	if (nam->sa_len != sizeof(*sinp))
 		return (EINVAL);
 
Index: sys/netinet/udp_usrreq.c
===================================================================
--- sys/netinet/udp_usrreq.c
+++ sys/netinet/udp_usrreq.c
@@ -1622,14 +1622,23 @@
 {
 	struct inpcb *inp;
 	struct inpcbinfo *pcbinfo;
+	struct sockaddr_in *sinp;
 	int error;
 
 	pcbinfo = udp_get_inpcbinfo(so->so_proto->pr_protocol);
 	inp = sotoinpcb(so);
 	KASSERT(inp != NULL, ("udp_bind: inp == NULL"));
 
-	if (nam->sa_family != AF_INET)
-		return (EAFNOSUPPORT);
+	sinp = (struct sockaddr_in *)nam;
+	if (nam->sa_family != AF_INET) {
+		/*
+		 * Preserve compatibility with old programs.
+		 */
+		if (nam->sa_family != AF_UNSPEC ||
+		    sinp->sin_addr.s_addr != INADDR_ANY)
+			return (EAFNOSUPPORT);
+		nam->sa_family = AF_INET;
+	}
 	if (nam->sa_len != sizeof(struct sockaddr_in))
 		return (EINVAL);