From owner-freebsd-net@FreeBSD.ORG Sat Oct 22 00:10:14 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 EE6091065673 for ; Sat, 22 Oct 2011 00:10:13 +0000 (UTC) (envelope-from qing.li@bluecoat.com) Received: from whisker.bluecoat.com (whisker.bluecoat.com [216.52.23.28]) by mx1.freebsd.org (Postfix) with ESMTP id 968D38FC0C for ; Sat, 22 Oct 2011 00:10:13 +0000 (UTC) Received: from PWSVL-EXCHTS-01.internal.cacheflow.com ([10.2.2.122]) by whisker.bluecoat.com (8.14.2/8.14.2) with ESMTP id p9M0AC2S024896 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Fri, 21 Oct 2011 17:10:12 -0700 (PDT) Received: from PWSVL-EXCMBX-01.internal.cacheflow.com ([fe80::15bc:12e2:4676:340f]) by PWSVL-EXCHTS-01.internal.cacheflow.com ([fe80::5c50:e2ba:8115:4223%20]) with mapi id 14.01.0289.001; Fri, 21 Oct 2011 17:10:06 -0700 From: "Li, Qing" To: Steven Hartland , "freebsd-net@freebsd.org" Thread-Topic: very strange arp problem after ip move - icmp works udp doesn't Thread-Index: AQHMkE0IYispNC6ALEmWKT0Fg7UO35WHfPDP Date: Sat, 22 Oct 2011 00:10:05 +0000 Message-ID: References: <02FFC9CF360C4E2F81B00B653DE1584E@multiplay.co.uk> In-Reply-To: <02FFC9CF360C4E2F81B00B653DE1584E@multiplay.co.uk> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [216.52.23.68] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: Subject: RE: very strange arp problem after ip move - icmp works udp doesn't X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 22 Oct 2011 00:10:14 -0000 You don't have the flowtable component enabled, do you ?=0A= =0A= --Qing=0A= =0A= ________________________________________=0A= From: owner-freebsd-net@freebsd.org [owner-freebsd-net@freebsd.org] on beha= lf of Steven Hartland [killing@multiplay.co.uk]=0A= Sent: Friday, October 21, 2011 4:44 PM=0A= To: freebsd-net@freebsd.org=0A= Subject: very strange arp problem after ip move - icmp works udp doesn't=0A= =0A= After a HD failure we moved an IP of one of our DNS=0A= servers to some new hardware.=0A= =0A= Now we are seeing some very strange behaviour on a number=0A= of machines when talking to the ip which was moved.=0A= =0A= Specifically it seems both icmp and tcp work just fine=0A= but udp doesn't.=0A= =0A= I've just done a trace from one such box and to my horror=0A= the tcpdump shows icmp and udp traffic for the same=0A= IP going to different mac's.=0A= =0A= icmp is going to the right mac and is working fine=0A= but udp is going to the wrong mac and isn't (as you=0A= would expect)=0A= =0A= In /var/log/messages there are arp messages=0A= which show the ip moving from -> to the correct macs=0A= but it seems like something somewhere is caching=0A= the resolution.=0A= =0A= arp -a also show's the correct result and arp -d -a doesn't=0A= help.=0A= =0A= So the question how on earth is udp resolving the mac=0A= to something different than icmp and tcp?=0A= =0A= To complicate matters even further some machines are=0A= working intermittently and the traces show the udp=0A= some times going to the right place and some times=0A= not.=0A= =0A= In all tests we're using just a dig with a specified=0A= server.=0A= =0A= The machines involved are all running 8.2-RELEASE on=0A= amd64=0A= =0A= Any help would be most appreciated as its causing chaos=0A= due to the IP that moved being our DNS servers and hence=0A= things are randomly stalling left right and center :(=0A= =0A= Regards=0A= Steve=0A= =0A= =0A= =0A= =0A= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=0A= This e.mail is private and confidential between Multiplay (UK) Ltd. and the= person or entity to whom it is addressed. In the event of misdirection, th= e recipient is prohibited from using, copying, printing or otherwise dissem= inating it or any information contained in it.=0A= =0A= In the event of misdirection, illegible or incomplete transmission please t= elephone +44 845 868 1337=0A= or return the E.mail to postmaster@multiplay.co.uk.=0A= =0A= _______________________________________________=0A= freebsd-net@freebsd.org mailing list=0A= http://lists.freebsd.org/mailman/listinfo/freebsd-net=0A= To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"=0A=