Index: head/libexec/rc/network.subr
===================================================================
--- head/libexec/rc/network.subr
+++ head/libexec/rc/network.subr
@@ -134,8 +134,6 @@
 	if ! noafif $1 && afexists inet6; then
 		if checkyesno ipv6_activate_all_interfaces; then
 			_ipv6_opts="-ifdisabled"
-		elif [ "$1" != "lo0" ]; then
-			_ipv6_opts="ifdisabled"
 		fi
 
 		# backward compatibility: $ipv6_enable
Index: head/sys/netinet6/nd6.c
===================================================================
--- head/sys/netinet6/nd6.c
+++ head/sys/netinet6/nd6.c
@@ -273,6 +273,10 @@
 
 	nd->flags = ND6_IFF_PERFORMNUD;
 
+	/* Set IPv6 disabled on all interfaces but loopback by default. */
+	if ((ifp->if_flags & IFF_LOOPBACK) == 0)
+		nd->flags |= ND6_IFF_IFDISABLED;
+
 	/* A loopback interface always has ND6_IFF_AUTO_LINKLOCAL.
 	 * XXXHRS: Clear ND6_IFF_AUTO_LINKLOCAL on an IFT_BRIDGE interface by
 	 * default regardless of the V_ip6_auto_linklocal configuration to
@@ -290,8 +294,11 @@
 	 */
 	if (V_ip6_accept_rtadv &&
 	    !(ifp->if_flags & IFF_LOOPBACK) &&
-	    (ifp->if_type != IFT_BRIDGE))
+	    (ifp->if_type != IFT_BRIDGE)) {
 			nd->flags |= ND6_IFF_ACCEPT_RTADV;
+			/* If we globally accept rtadv, assume IPv6 on. */
+			nd->flags &= ~ND6_IFF_IFDISABLED;
+	}
 	if (V_ip6_no_radr && !(ifp->if_flags & IFF_LOOPBACK))
 		nd->flags |= ND6_IFF_NO_RADR;