From owner-freebsd-net@freebsd.org Fri Sep 6 03:56:18 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 410A5DE776 for ; Fri, 6 Sep 2019 03:56:18 +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 46PkJ11zztz3JbS for ; Fri, 6 Sep 2019 03:56:16 +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=cqmkOV86WRguOy9cEVFzV/hzoYjmkoEahBRpxkBeDFE=; b=pGFUXRJpUY/lT8UpjE6nZ2k2ah v73+eZz7IIBULrZ+M8qiPQC8h0vYu9ZhTqD24s9G2Re9qSCUzDvhFdoumg7DAq2ZqHhPDHtWn4qSR BB5SlP/tJjDxffLUcxA/+lvErcNcjshc0CSbMaX+tocTfn4BIM6K/PfkOHw+q88VdBEw=; Received: from vas by admin.sibptus.ru with local (Exim 4.92.1 (FreeBSD)) (envelope-from ) id 1i65M0-000C0X-5e for freebsd-net@freebsd.org; Fri, 06 Sep 2019 10:56:08 +0700 Date: Fri, 6 Sep 2019 10:56:08 +0700 From: Victor Sudakov To: freebsd-net@freebsd.org Subject: Re: Several IPv6 routers and default gateway choice Message-ID: <20190906035608.GA45741@admin.sibptus.ru> References: <20190830021228.GA66465@admin.sibptus.ru> <20190830.121543.1108900942284640156.hrs@allbsd.org> <20190901141047.GA56954@admin.sibptus.ru> <20190902.044135.1812305046881448068.hrs@allbsd.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="k1lZvvs/B4yU6o8G" Content-Disposition: inline In-Reply-To: <20190902.044135.1812305046881448068.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: 46PkJ11zztz3JbS X-Spamd-Bar: -------- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=sibptus.ru header.s=20181118 header.b=pGFUXRJp; 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 [-8.59 / 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]; 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(-3.00)[ip: (-9.50), ipnet: 2001:19f0:5000::/38(-4.75), asn: 20473(-0.69), country: US(-0.05)]; DKIM_TRACE(0.00)[sibptus.ru:+]; NEURAL_HAM_SHORT(-0.99)[-0.991,0]; 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: Fri, 06 Sep 2019 03:56:18 -0000 --k1lZvvs/B4yU6o8G Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hiroki Sato wrote: > va> Can any IPv6 unicast or link-local address be configured as an anycast > va> address of a router? >=20 > Yes. There is no restriction about address scope. >=20 > You might want to read RFC 4291, which defines Subnet-Router anycast > address, and RFC 2526, which defines the other reserved IPv6 subnet > anycast addresses. In general, the former one can be used for > routing purpose. Interestingly, RFC4291 says that "All routers are required to support the Subnet-Router anycast addresses for the subnets to which they have interfaces." In practice, I don't observe this. A FreeBSD router does not configure such an address automatically, for example. RFC2526 is dim, I think it's because of this RFC the last usable address on a subnet ends in ff7f instead of ffff. I wonder if anyone anywhere uses those subnet anycast addresses. --=20 Victor Sudakov, VAS4-RIPE, VAS47-RIPN 2:5005/49@fidonet http://vas.tomsk.ru/ --k1lZvvs/B4yU6o8G Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJdcdjYAAoJEA2k8lmbXsY0ZkwIAI7CqOwHnSuTok5E8rdFoU4/ NkyphmkaZtJT1T8zczdQc8H3lVEMH5mucXRLkXv3pmCYfY6DGsXVhC5tCf5fCaFD +i2CnArD3nP4r1NtGehJNXwM2PsD2KJBMf+nOXSNnsRjL5w4cL1yR1edm2cggfU0 RoR+gclhddhTgmkBiQOZkbuJhfHfMv6QJcpwFFlo7hDl4SO2yAUvZq5juml21wnX s/1gAskyH6G8C5MD8xBMMJ0qm3ghllZrj2gzbiE0lgmX9z8y1c9CK2msLz7l2/aL RlP6CjKwqgrzdLS/lzA351sHAz6Z5Z+dluQfvia3EkywP3aFNbUzHPvxoJSqMjE= =ZKVL -----END PGP SIGNATURE----- --k1lZvvs/B4yU6o8G--