From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Wei Subject: Is there any necessary to add multicast route for a loopback device? Date: Wed, 30 Nov 2011 15:38:37 +0800 Message-ID: <4ED5DD7D.10908@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit To: netdev Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:53506 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753904Ab1K3Hi2 (ORCPT ); Wed, 30 Nov 2011 02:38:28 -0500 Received: from tang.cn.fujitsu.com (tang.cn.fujitsu.com [10.167.250.3]) by song.cn.fujitsu.com (Postfix) with ESMTP id A550C17012D for ; Wed, 30 Nov 2011 15:38:17 +0800 (CST) Received: from mailserver.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id pAU7cG9i008224 for ; Wed, 30 Nov 2011 15:38:16 +0800 Sender: netdev-owner@vger.kernel.org List-ID: Hi all, I found that since Fedora 15, it use systemd as the 'init'. When systemd start it would config the ipv6 address(::1/128) for 'lo' and start it. While adding this address to 'lo', kernel will call addrconf_add_mroute() to set a multicast route for 'lo' with rt->dst.error = -ENETUNREACH. After that, when I send multi- cast message, the route subsystem return a route with .error set to NETUNREACH. Is there any necessary to add multicast route for a loopback device?