From owner-freebsd-net@freebsd.org Thu Sep 12 04:14:13 2019 Return-Path: Delivered-To: freebsd-net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id D956FE9FD8 for ; Thu, 12 Sep 2019 04:14:13 +0000 (UTC) (envelope-from vas@mpeks.tomsk.su) Received: from admin.sibptus.ru (admin.sibptus.ru [IPv6:2001:19f0:5001:21dc::10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 46TQPx2VdYz3HwH for ; Thu, 12 Sep 2019 04:14:13 +0000 (UTC) (envelope-from vas@mpeks.tomsk.su) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sibptus.ru; s=20181118; h=In-Reply-To:Message-ID:Subject:To:From:Date; bh=MrxP52zALDwG3B3VwUt82mYq/IzGAuk2uzNAGcBvLx8=; b=dZIK7nRLiv5Tl1svZXaLn/6/Mz mwLQ90mx/LhcPJRdFkO7jQ5yTe7ecUXbYlHW6WA2+VVG6+I4TMXqPEn5PyIuHZIqs1edvtDja3DYn a2M23FhVNlsjQ0pPR+sk4DC50OZ694Vr3Swwp4IDgfwUF4CU6TBhcBuy90qIaJ0IsJRA=; Received: from vas by admin.sibptus.ru with local (Exim 4.92.2 (FreeBSD)) (envelope-from ) id 1i8GUm-0000li-4k for freebsd-net@freebsd.org; Thu, 12 Sep 2019 11:14:12 +0700 Date: Thu, 12 Sep 2019 11:14:12 +0700 From: Victor Sudakov To: freebsd-net@freebsd.org Subject: Re: Several IPv6 routers and default gateway choice Message-ID: <20190912041412.GA2851@admin.sibptus.ru> References: <20190901141047.GA56954@admin.sibptus.ru> <20190902.044135.1812305046881448068.hrs@allbsd.org> <20190906035608.GA45741@admin.sibptus.ru> <20190912.123249.93293774363511628.hrs@allbsd.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="UugvWAfsgieZRqgk" Content-Disposition: inline In-Reply-To: <20190912.123249.93293774363511628.hrs@allbsd.org> X-PGP-Key: http://admin.sibptus.ru/~vas/ X-PGP-Fingerprint: 10E3 1171 1273 E007 C2E9 3532 0DA4 F259 9B5E C634 User-Agent: Mutt/1.12.1 (2019-06-15) Sender: Victor Sudakov X-Rspamd-Queue-Id: 46TQPx2VdYz3HwH X-Spamd-Bar: ------- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=sibptus.ru header.s=20181118 header.b=dZIK7nRL; dmarc=none; spf=pass (mx1.freebsd.org: domain of vas@mpeks.tomsk.su designates 2001:19f0:5001:21dc::10 as permitted sender) smtp.mailfrom=vas@mpeks.tomsk.su X-Spamd-Result: default: False [-7.69 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[sibptus.ru:s=20181118]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+mx:c]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.20)[multipart/signed,text/plain]; TO_DN_NONE(0.00)[]; DMARC_NA(0.00)[tomsk.su]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; IP_SCORE(-3.09)[ip: (-9.68), ipnet: 2001:19f0:5000::/38(-4.84), asn: 20473(-0.87), country: US(-0.05)]; DKIM_TRACE(0.00)[sibptus.ru:+]; SIGNED_PGP(-2.00)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:20473, ipnet:2001:19f0:5000::/38, country:US]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Sep 2019 04:14:13 -0000 --UugvWAfsgieZRqgk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hiroki Sato wrote: > va> > va> Can any IPv6 unicast or link-local address be configured as an = anycast > va> > va> address of a router? > va> > > va> > Yes. There is no restriction about address scope. > va> > > va> > You might want to read RFC 4291, which defines Subnet-Router anyca= st > va> > address, and RFC 2526, which defines the other reserved IPv6 subnet > va> > anycast addresses. In general, the former one can be used for > va> > routing purpose. > va> > va> Interestingly, RFC4291 says that "All routers are required to support > va> the Subnet-Router anycast addresses for the subnets to which they have > va> interfaces." In practice, I don't observe this. A FreeBSD router does > va> not configure such an address automatically, for example. >=20 > They will be automatically configured when an ipv6_prefix_IF > rc.conf(5) variable is used to configure a prefix: >=20 > ----(from rc.conf(5) man page)---- > ipv6_prefix_ed0=3D"2001:db8:1:0 2001:db8:2:0" >=20 > is equivalent to the following: >=20 > ifconfig_ed0_alias0=3D"inet6 2001:db8:1:: eui64 prefixlen 64" > ifconfig_ed0_alias1=3D"inet6 2001:db8:1:: prefixlen 64 anycast" > ifconfig_ed0_alias2=3D"inet6 2001:db8:2:: eui64 prefixlen 64" > ifconfig_ed0_alias3=3D"inet6 2001:db8:2:: prefixlen 64 anycast" >=20 > These Subnet-Router anycast addresses will be added only when > ipv6_gateway_enable is YES. > ---------------------------------- Dear Hiroki, You are an invaluable source of information. I wish all the above should make it into the Handbook, the chapter on IPv6. --=20 Victor Sudakov, VAS4-RIPE, VAS47-RIPN 2:5005/49@fidonet http://vas.tomsk.ru/ --UugvWAfsgieZRqgk Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJdecYUAAoJEA2k8lmbXsY0rV8H+wcqmOBz9RD/Rfg7xPSH4Hat B5uZoHEkCnRS9XzCechvjFI0X76BmT7Rhkqlkkp0xUr6avVJl6dwvEnEfPFCCQze ZS+gMLGgEwWYK0Og5irsle9Clp4kajqtuaUT6v2EksxLjn55eaHk78EU6NXwixv5 IaezhI4fA/p0nMEPSqHog+6usVCODQe+QJ/xxvSjmsGNOLipr6hwyWRVl+o2MuIK 5mI/EIIxV/p3wP7DzBlR8jqahw8e3Q/svuq2HTdM+zJKt9WqpMBMwWh6mS5Wbv8P ubFT6fzLy50ip66CB7jfUmlavQ3q0JPEzKrZ/sK95oXEgiVoW2wjjGKRS1jy2X8= =3UiN -----END PGP SIGNATURE----- --UugvWAfsgieZRqgk--