From owner-freebsd-questions@FreeBSD.ORG Wed Nov 24 16:52:57 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7E70116A4CE for ; Wed, 24 Nov 2004 16:52:57 +0000 (GMT) Received: from lorna.circlesquared.com (host217-45-219-85.in-addr.btopenworld.com [217.45.219.85]) by mx1.FreeBSD.org (Postfix) with ESMTP id 94AF043D62 for ; Wed, 24 Nov 2004 16:52:56 +0000 (GMT) (envelope-from peter@circlesquared.com) Received: from [127.0.0.1] (localhost.circlesquared.com [127.0.0.1]) iAOGqoHj059825; Wed, 24 Nov 2004 16:52:51 GMT (envelope-from peter@circlesquared.com) Message-ID: <41A4BC62.3080503@circlesquared.com> Date: Wed, 24 Nov 2004 16:52:50 +0000 From: Peter Risdon User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.3) Gecko/20041124 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Dick Davies References: <20041123233501.GA82229@dogma.freebsd-uk.eu.org> <5557305861.20041124004849@hexren.net> <20041124000014.GA83249@dogma.freebsd-uk.eu.org> <8763344284.20041124022927@hexren.net> <20041124141737.GA11648@dogma.freebsd-uk.eu.org> <5315017844.20041124160806@hexren.net> <20041124152355.GD11648@dogma.freebsd-uk.eu.org> <10516350570.20041124163019@hexren.net> <41A4AAEF.6080202@circlesquared.com> <20041124163324.GJ12945@lb.tenfour> In-Reply-To: <20041124163324.GJ12945@lb.tenfour> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: FreeBSD Questions Subject: Re: 4 part domain names X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Nov 2004 16:52:57 -0000 Dick Davies wrote: > * Peter Risdon [1140 15:40]: > >>Hexren wrote: >> >>>JM> On Wed, Nov 24, 2004 at 04:08:06PM +0100, Hexren wrote: >>>JM> : location. 510 could identify a rack or a datacenter so that >>>JM> : us.510.mail.example.com means "a mail server in the datecenter with >>>JM> : the id 510 which serves the United States". >>> >>>JM> So 'us.510.mail' is an atomic, arbitrary identifier. All three as a >>>unit >>>JM> identify a certain node, and are selected purely for convenience of >>>human >>>JM> operators, right? >>> >>>I would say yes. >>> >>> >>>JM> I'm just making sure that the network doesn't treat 'us.510.mail' any >>>JM> different than it would treat 'foobar', right? >>> >>>I would say yes too. >> >> >>How does this square with the fact, as I understand it, that I can >>delegate authority for mail.example.com to new nameservers which can >>then publish host information about this zone? > > > That's got nothing to do with the network. > For example, I can create a host in example.com called > > us.510.mail > > and you can't stop me (evil laughter). > > Sent the RFC mail prematurely... RFC 952 says: A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.). Note that periods are only allowed when they serve to delimit components of "domain style names". (See RFC-921, "Domain Name System Implementation Schedule", for background). So I guess you could, but it wouldn't be canonical. If authority ever gets delegated for mail.example.com, then for 510.mail.example.com, then a host called us is published, there's going to be a bit of a problem with your network. Peter. -- the circle squared network systems and software http://www.circlesquared.com