From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264373AbUEXUiK (ORCPT ); Mon, 24 May 2004 16:38:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264689AbUEXUiK (ORCPT ); Mon, 24 May 2004 16:38:10 -0400 Received: from hyperion.haystack.edu ([192.52.65.1]:35475 "EHLO hyperion.haystack.edu") by vger.kernel.org with ESMTP id S264373AbUEXUhP (ORCPT ); Mon, 24 May 2004 16:37:15 -0400 Message-ID: <40B25CFA.3000105@haystack.mit.edu> Date: Mon, 24 May 2004 16:37:14 -0400 From: Frank Lind User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.5) Gecko/20030925 X-Accept-Language: en-us, en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: knobi@knobisoft.de Subject: Multicast problems between 2.4.20 and 2.4.21? Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, Was there ever a resolution to the multicast issues with kernels beyond 2.4.20? I have a very similar problem that has shown up with code which works fine prior with 2.4.20-6smp (Redhat 9) and then stops working for later kernels. I ran into this upgrading a machine to RedHat Enterprise (2.4.21-9.ELsmp) but it also happens under Fedora (2.6.5-1.358smp). I was going to try some separate kernel compiles and also a different distribution when I get a chance to try to localize the change. I haven't been able to find a clear reason why this is happening yet. I was wondering if anyone had any additional insights beyond what showed up in the kernel mailing lists so far (i.e. Any changes in Multicast code between 2.4.20 and 2.4.22/23)? I am able to get the multicasting to work under these kernels by changing my bind calls to use the INADDR_ANY instead of binding to the address and port I'm using for the multicast group. I haven't found good documentation that this is the "correct" way to do this but I ran into some comments for multicast under ipv6 which made me think it was worth a try. This substitution gets the machines multicasting but I've had some problems that appear to be the switch selectively deciding to deliver data or not depending on if certain machines connect to the multicast group. (This needs more testing but basically if a machine using the 2.4.20 kernel joins then some of the newer kernel machines stop getting packets for reasons I don't understand yet). I noted it was asked why the network switch might matter. There is a note from HP on their Procurve switches indicates that certain IP addresses are not IGMP filtered. In particular 224.0.0.x gets no IGMP filtering : http://www.hp.com/rnd/pdfs/IGMP_Tech_Note.pdf I got bit by this one a while back in that my network was getting flooded despite using IGMP in the code. -- Frank -- Frank D. Lind email: flind@haystack.mit.edu MIT Haystack Observatory WWW: http://www.haystack.mit.edu Route 40 tel: 781 981 5570 Westford, MA 01886 USA fax: 781 981 5766