Date: Mon, 13 Aug 2001 05:19:32 +0900 From: JINMEI Tatuya / =?ISO-2022-JP?B?GyRCP0BMQEMjOkgbKEI=?= <jinmei@isl.rdc.toshiba.co.jp> To: raviprasad20@netscape.net Cc: freebsd-net@FreeBSD.ORG Subject: Re: prefixes advertised by routers. Message-ID: <y7vk809ni97.wl@condor.jinmei.org> In-Reply-To: <20B5BA4D.2584EAB3.9513E96F@netscape.net> References: <20B5BA4D.2584EAB3.9513E96F@netscape.net>
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>>>>> On Thu, 09 Aug 2001 01:04:54 -0400, >>>>> raviprasad20@netscape.net said: > Assume that two prefix are advertised by router to hosts in the network. After some time the administrator deletes one of the prefixes and the future router advertisement will carry only one prefix. > What will hosts do with the deleted prefix? > Whether the addresses will be deleted after some time? What is this time? After the lifetime of the removed prefix expires. >> From the specs i found that the addresses are deleted only if the router advertises prefix with valid life time of zero. Whether the rtadvd daemon has to send any such message with deleted prefix life time set to zero? Yes. However, we should also note that the autoconfigured address is not (immediately) invalidated by an RA with the valid lifetime being 0, unless the RA is authenticated by IPsec. We'll see two-hour lag before the actual expiration. For more details, please read carefully RFC 2462. > I feel that the addresses should be deleted immediately if a router stops advertising the prefix. No, they shouldn't. First of all, there is no effective mechanism that a host knows a router stops advertising RA. The only thing it can is to decrement lifetimes when it does not hear succeeding RAs. 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
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