From owner-freebsd-net@freebsd.org Sat Sep 7 02:06:58 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 24547DF91C for ; Sat, 7 Sep 2019 02:06:58 +0000 (UTC) (envelope-from kob6558@gmail.com) Received: from mail-oi1-x233.google.com (mail-oi1-x233.google.com [IPv6:2607:f8b0:4864:20::233]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 46QHqN2cWGz3wd1 for ; Sat, 7 Sep 2019 02:06:55 +0000 (UTC) (envelope-from kob6558@gmail.com) Received: by mail-oi1-x233.google.com with SMTP id z6so1079209oix.9 for ; Fri, 06 Sep 2019 19:06:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=aKdiMrejThJh1JCedONiGuq3pZiheHOHF/uTNm5odlo=; b=ssAWAEbXZbsvJlGnIwCMG4uRiYXv26yohXGgnFtdBis00fBtBQMYU54tBfdenGWEsZ IO84F17u5Fyg5tohpuJUgLUx7iRXB2HjWyRY/LCoHodAg7gGPE5ATQ0jiPmyfypj3EOk Q/50/Gt8XSQyoBSVtDToTRtTpir9HInf9v5tbROQXAgpAmFdWTC3ptUojUf+Xri5OmAJ ybHbyRUHmx0l1MVa6we9QrIGBhEBYJIWg3HOYmNn3Ow5B/L8um7EucKVYyM13wYNnRAQ Ow/bNmOMgjVqD/zw2ROqjBVXG521PrXPhJ2q5VaHx7mEDVTjiyXQlu8gWEFNXEwp0hvj dAXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=aKdiMrejThJh1JCedONiGuq3pZiheHOHF/uTNm5odlo=; b=PFa6QkZlHS/1S8j8G4LqbMcPi3+7JTM7jW45DGWkI1nWFWjrUcaexJMxuW/WaRodqq sAmvNXxy2WE1MTPJLi2LCHdg9qK12wK6kmsAX6oA2dG0DFWyDhf88U/PzeK4AkilnKOR Gok+tj0kiePdnNw6xLplFU04wFQMMlp3xkDLQc7R7rIcUBPfPwzZXyvBMsSyb9xzuijq soOqQ0KYGVe36QS6Rg+TsOslBQeejGa5GeEvkTC+qYOm97XrD1NcEz0PMb1IPuQY6ulh 93uV726PQqaWiVHZFRGuWpreN+MmjstfAyEMejbMEyDT6QGxcJJKF/zcONjxAAVB9G+H DNoQ== X-Gm-Message-State: APjAAAV6eEzjvx3wANdkM/H/henr0zFBHXzIlnKxWKrMhtdAM/0mVZbe hF06uYudU1YSIld4gdKugSp/awbIjo7TfCkbmJjdntTB X-Google-Smtp-Source: APXvYqzE+CUsBH2wT0G/ZkToVX66T9YWmx+myIJR8IEsPxBqBHpZzlTUHvILOEaJJ41pOffRvlc+NcWh5z0J4DwXINM= X-Received: by 2002:aca:5c57:: with SMTP id q84mr9656191oib.176.1567822014445; Fri, 06 Sep 2019 19:06:54 -0700 (PDT) MIME-Version: 1.0 References: <20190830021228.GA66465@admin.sibptus.ru> <20190830.121543.1108900942284640156.hrs@allbsd.org> <20190901141047.GA56954@admin.sibptus.ru> <20190902.044135.1812305046881448068.hrs@allbsd.org> <20190906035608.GA45741@admin.sibptus.ru> In-Reply-To: <20190906035608.GA45741@admin.sibptus.ru> From: Kevin Oberman Date: Fri, 6 Sep 2019 19:06:36 -0700 Message-ID: Subject: Re: Several IPv6 routers and default gateway choice To: Victor Sudakov Cc: freebsd-net X-Rspamd-Queue-Id: 46QHqN2cWGz3wd1 X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20161025 header.b=ssAWAEbX; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of kob6558@gmail.com designates 2607:f8b0:4864:20::233 as permitted sender) smtp.mailfrom=kob6558@gmail.com X-Spamd-Result: default: False [-3.70 / 15.00]; FREEMAIL_FROM(0.00)[gmail.com]; R_SPF_ALLOW(-0.20)[+ip6:2607:f8b0:4000::/36]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; RCPT_COUNT_TWO(0.00)[2]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; NEURAL_HAM_SHORT(-1.00)[-0.998,0]; FORGED_SENDER(0.30)[rkoberman@gmail.com,kob6558@gmail.com]; IP_SCORE(0.00)[ip: (-8.14), ipnet: 2607:f8b0::/32(-2.75), asn: 15169(-2.27), country: US(-0.05)]; MIME_TRACE(0.00)[0:+,1:+,2:~]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; FROM_NEQ_ENVFROM(0.00)[rkoberman@gmail.com,kob6558@gmail.com]; DWL_DNSWL_NONE(0.00)[gmail.com.dwl.dnswl.org : 127.0.5.0]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20161025]; FROM_HAS_DN(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-net@freebsd.org]; IP_SCORE_FREEMAIL(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[3.3.2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.b.8.f.7.0.6.2.list.dnswl.org : 127.0.5.0]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[] Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.29 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: Sat, 07 Sep 2019 02:06:58 -0000 On Thu, Sep 5, 2019 at 8:56 PM Victor Sudakov wrote: > Hiroki Sato wrote: > > va> Can any IPv6 unicast or link-local address be configured as an > anycast > > va> address of a router? > > > > Yes. There is no restriction about address scope. > > > > 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. > I have to look it up on the status page, but I thought 2526 had been deprecated back before I retired. I thought I discovered this while setting up anycast for our DNS servers. I'll look when I get back from walking our dog. (Priorities change when you retire.)