From owner-freebsd-net@FreeBSD.ORG Thu Nov 10 19:40:09 2011 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1C4141065670 for ; Thu, 10 Nov 2011 19:40:09 +0000 (UTC) (envelope-from ddesimone@verio.net) Received: from relay1-bcrtfl2.verio.net (relay1-bcrtfl2.verio.net [131.103.218.142]) by mx1.freebsd.org (Postfix) with ESMTP id C761E8FC12 for ; Thu, 10 Nov 2011 19:40:08 +0000 (UTC) Received: from iad-wprd-xchw01.corp.verio.net (iad-wprd-xchw01.corp.verio.net [198.87.7.164]) by relay1-bcrtfl2.verio.net (Postfix) with ESMTP id D445EB0380BE for ; Thu, 10 Nov 2011 14:40:07 -0500 (EST) thread-index: Acyf4I0BA+Tu7rX+Sc6HbV3aqx+2Uw== Received: from hometx-733b1p1.corp.verio.net ([10.144.2.53]) by iad-wprd-xchw01.corp.verio.net over TLS secured channel with Microsoft SMTPSVC(6.0.3790.4675); Thu, 10 Nov 2011 14:40:06 -0500 Received: by hometx-733b1p1.corp.verio.net (sSMTP sendmail emulation); Thu, 10 Nov 2011 13:40:05 -0600 Date: Thu, 10 Nov 2011 13:40:05 -0600 Content-Transfer-Encoding: 7bit From: "David DeSimone" To: Content-Class: urn:content-classes:message Importance: normal Priority: normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.3790.4862 Message-ID: <20111110194004.GB7844@verio.net> Mail-Followup-To: freebsd-net@freebsd.org References: <96A5211A-398B-4773-8C6A-2D772D241CF0@msu.edu> <20111110065135.GS71907@FreeBSD.org> <6A964045-2ADF-42EC-8AC4-00179FDBE4D9@msu.edu> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-reply-to: <6A964045-2ADF-42EC-8AC4-00179FDBE4D9@msu.edu> Precedence: bulk User-Agent: Mutt/1.5.20 (2009-12-10) X-OriginalArrivalTime: 10 Nov 2011 19:40:06.0217 (UTC) FILETIME=[8C4BCB90:01CC9FE0] Subject: Re: FreeBSD 9 and ARP multicast source address error messages X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Nov 2011 19:40:09 -0000 Alexander Wittig wrote: > > Nov 10 12:25:45 bt kernel: in_arp: 03:bf:23:09:44:e4 is multicast > Nov 10 12:25:45 bt kernel: in_arp: 03:bf:23:09:44:87 is multicast > [...] > > I'm not an expert on networking, but is this condition of ignoring > such an ARP packet really a noteworthy event? I.e. is this something > that should not occur in "normal" operation according to the ARP > specifications? If this is mostly for kernel developers, maybe it > should only be enabled in debug kernel builds? I found this tread enlightening on the subject: http://fixunix.com/tcp-ip/66685-arp-reply-containing-multicast-mac-ok.html In particular the reference to RFC 1812 which states: A router MUST not believe any ARP reply that claims that the Link Layer address of another host or router is a broadcast or multicast address. This requirement is the reason why multicast ARP replies are problematic, and why Microsoft's NLB implementation often causes heartburn within the network. -- David DeSimone == Network Admin == fox@verio.net "I don't like spinach, and I'm glad I don't, because if I liked it I'd eat it, and I just hate it." -- Clarence Darrow This email message is intended for the use of the person to whom it has been sent, and may contain information that is confidential or legally protected. If you are not the intended recipient or have received this message in error, you are not authorized to copy, distribute, or otherwise use this message or its attachments. Please notify the sender immediately by return e-mail and permanently delete this message and any attachments. Verio, Inc. makes no warranty that this email is error or virus free. Thank you.