From - Fri Jan 2 13:28:32 1998 X-Received: from data.pa.vix.com [204.152.184.37] by gw.home.vix.com via ESMTP id OAA07484 for ; Mon, 29 Dec 1997 14:19:29 -0800 (PST) env-from (news@camel20.mindspring.com) X-Received: from jazz.ncren.net [128.109.131.6] by data.pa.vix.com via ESMTP id OAA22988 for ; Mon, 29 Dec 1997 14:19:28 -0800 (PST) env-from (news@camel20.mindspring.com) X-Received: from camel20.mindspring.com (camel20.mindspring.com [207.69.200.70]) by jazz.ncren.net (8.7.4/8.7.3) with ESMTP id RAA09296 for ; Mon, 29 Dec 1997 17:17:09 -0500 (EST) X-Received: (from news@localhost) by camel20.mindspring.com (8.8.5/8.7.3) id RAA23338; Mon, 29 Dec 1997 17:17:08 -0500 (EST) X-To: comp-protocols-dns-bind@moderators.uu.net Path: hubcap.clemson.edu!cssun.mathcs.emory.edu!metro.atlanta.com!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!howland.erols.net!news-peer.gip.net!news.gsl.net!gip.net!news.idt.net!nntp2.cerf.net!nntp.ni.net!news.pn.com!nntp.pn.com!data.ramona.vix.com!vixie!nobody From: cricket@acmebw.com (Cricket Liu) Newsgroups: comp.protocols.dns.bind Subject: Re: About those root servers... Date: Mon, 29 Dec 1997 22:18:00 GMT Organization: Acme Byte & Wire Lines: 52 Message-ID: <34aa1faf.1914172@news.mindspring.com> References: Reply-To: cricket@acmebw.com X-Nntp-Posting-Host: ip102.denver8.co.pub-ip.psi.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Server-Date: 29 Dec 1997 22:17:08 GMT X-Newsreader: Forte Agent 1.5/32.451 Approved: usenet@vix.com Xref: hubcap.clemson.edu comp.protocols.dns.bind:4520 On Mon, 29 Dec 1997 05:45:28 -0600, "Martin, Kevin" wrote: >> I have what is probably a real basic question: >> >> Are all of the root servers on the Internet clones of each other? They all have identical copies of the root zone, though individual roots are authoritative for other zones, too. >> If not, if I do a lookup on an address, say, just for an example, >> 15.255.152.5(which, by the way, resolves to relpilot.cns.hp.com) how >> does the root server return this info? It's my understanding that the >> request would go to the first root server and, if it knows who can >> answer the question about 15.in-addr.arpa, it will query that dns >> server and return the reply. No, the roots don't do any querying for you. You query a name server close to you, and it may send a query to a root, asking for the PTR record for 5.152.255.15.in-addr.arpa. The root will probably refer your name server to the 15.in-addr.arpa name servers, which are run by HP. Your name server will follow up by sending a query to a 15.in-addr.arpa name server, which will probably refer it to a 152.255.15.in-addr.arpa name server. Your name server will follow up again, and the name server it queries will return the PTR record. >> But what if the first root server DOES NOT know who is authoritative >> for the 15.in-addr.arpa? The root name servers, by virtue of the fact that they're authoritative for the root zone, know where the arpa name servers are, and can refer querying name servers to them. In fact, most of the root name servers are also authoritative for arpa and in-addr.arpa, so they can refer directly to the 15.in-addr.arpa name servers. >> Who does it query then? As I said, the roots don't query anyone. The resolution process typically uses two different kinds of queries: recursive and non-recursive. The query your resolver sends to your local name server is recursive, and asks that the name server respond with an answer, not a referral. The query your local name server sends to other name servers, including the roots, is non-recursive, and asks for any answer, including a referral. (In fact, the roots will respond with referrals even to recursive queries.) >> If the root server doesn't know the answer, does it query >> the next root server in the list? There's no need to, since all roots have identical copies of the root zone.