From owner-freebsd-net Sun Jul 1 23:27:41 2001 Delivered-To: freebsd-net@freebsd.org Received: from shuttle.wide.toshiba.co.jp (shuttle.wide.toshiba.co.jp [202.249.10.124]) by hub.freebsd.org (Postfix) with ESMTP id 592EA37B401 for ; Sun, 1 Jul 2001 23:27:37 -0700 (PDT) (envelope-from jinmei@isl.rdc.toshiba.co.jp) Received: from localhost ([3ffe:501:4819:2000:200:39ff:fe97:3f1e]) by shuttle.wide.toshiba.co.jp (8.9.1+3.1W/8.9.1) with ESMTP id PAA12935; Mon, 2 Jul 2001 15:28:47 +0900 (JST) Date: Mon, 02 Jul 2001 15:27:26 +0900 Message-ID: From: JINMEI Tatuya / =?ISO-2022-JP?B?GyRCP0BMQEMjOkgbKEI=?= To: "Kevin Oberman" Cc: freebsd-net@FreeBSD.ORG Subject: Re: Odd IPv6 behavior when not connected to IPv6 net In-Reply-To: <200106291628.f5TGSsc13240@ptavv.es.net> References: <200106291628.f5TGSsc13240@ptavv.es.net> User-Agent: Wanderlust/2.6.0 (Twist And Shout-pre) Emacs/21.0 Mule/5.0 (SAKAKI) Organization: Research & Development Center, Toshiba Corp., Kawasaki, Japan. MIME-Version: 1.0 (generated by SEMI 1.13.7 - "Awazu") Content-Type: text/plain; charset=US-ASCII X-Dispatcher: imput version 980905(IM100) Lines: 41 Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org >>>>> On Fri, 29 Jun 2001 09:28:54 -0700, >>>>> "Kevin Oberman" said: >> That is, if we do not have any default router (hear from RA), we >> should regard all IPv6 prefixes as on-link. To implement this trick, >> we use the "default interface", and install the default route as an >> interface direct route to the interface. > I think the basic idea in the RFC may be reasonable. It only breaks > when the link selected is loopback. Had the stack tried to connect to > a physical link, this would have worked as intended, but loopback will > always be the wrong answer if it is the link used. Just to make it sure, even if you specify a non-loopback interface as the default, you should still (usually) see a long delay before the connection attempt by IPv6 fails, because this type of error is not a hard error for TCP (like "no route to host"). The delay would be about 1 minute. I don't think most users do not tolerate the delay, especially when the IPv4 connection can be established. >> Thus, for the moment, I agree that we should turn the default >> interface off by default. For a longer term solution, we might have >> to consider a better source address selection algorithm, >> e.g. described in draft-ietf-ipngwg-default-addr-select-04.txt. Then >> IPv4 would be preferred in this case. > This is certainly reasonable, too. But the step of not allowing the lo > interface to qualify as the link for the default route seems like > something that should be done as well. > Of course, there may be some reason to want default to point at lo, > but I can't think of a good one. I don't have any objection to changing the default interface to a non-loopback one, *if the default is ever defined*. I'm arguing that it would be safe *not to specify the default interface by default*. JINMEI, Tatuya Communication Platform Lab. Corporate R&D Center, Toshiba Corp. jinmei@isl.rdc.toshiba.co.jp To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message