Date: Wed, 28 Feb 2001 08:12:27 -0800 From: Dan Peterson <danp@danp.net> To: freebsd-net@freebsd.org Subject: Re: DNS problems with hub.freebsd.org Message-ID: <20010228081227.A76505@danp.net> In-Reply-To: <Pine.BSF.4.05.10102281050260.27183-100000@black.purplecat.net>; from peter@black.purplecat.net on Wed, Feb 28, 2001 at 10:55:21AM -0500 References: <Pine.BSF.4.05.10102281050260.27183-100000@black.purplecat.net>
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Peter Brezny <peter@black.purplecat.net> wrote: > The rest of the internet appears to have figured out the forward and > reverse lookups for > > ns1.sysadmin-inc.com <--> 209.16.228.145 > > but eventhough hub.freebsd.org knows > 209.16.228.145 --> ns1.sysadmin-inc.com > > It's still under the incorrect assumption (for the past two weeks or more) > that: > ns1.sysadmin-inc.com --> 209.16.228.150 Using the handy dnstrace utility from the djbdns suite (http://cr.yp.to/djbdns.html), it's easy to see where the problem comes from. The root com/net/org servers have their own idea what "ns1.sysadmin-inc.com" points to. Since all queries for this host start at the roots and then move up to the com/net/org roots, resolvers stop when they get to the com/net/org roots because they provide an authoritive answer. Observe: 1 ns1._sysadmin-inc.com_ 207.230.75.50 135439 A 209.16.228.150 1 ns1.sysadmin-inc.com 192.36.144.133 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 192.41.162.30 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 198.17.208.67 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 198.41.3.101 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 198.41.3.38 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 203.181.106.5 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 205.188.185.18 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 207.200.81.69 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 208.206.240.5 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 210.132.100.101 172800 A 209.16.228.150 1 ns1.sysadmin-inc.com 213.177.194.5 172800 A 209.16.228.150 1 ns1._sysadmin-inc.com_ 207.230.75.34 86400 A 209.16.228.145 1 ns1._sysadmin-inc.com_ 209.16.228.140 86400 A 209.16.228.145 1 ns1._sysadmin-inc.com_ 209.16.228.145 86400 A 209.16.228.145 1 ns1._sysadmin-inc.com_ 209.16.228.150 86400 A 209.16.228.145 "1" is the query type. 1 is A. the second field is what the IP in the third field was being queried for. Naturally, the last section is what was returned. I've inserted underscores to underline (as dnstracesort does, but with actual underline terminal codes) what the IP being queried is supposed to be authoritive for. Since I started my dnstrace with [a-l].gtld-servers.net listed as my "roots," queries to them have no underlining since they're authoritive for everything. All the root servers say ns1.sysadmin-inc.com is 209.16.228.150. Notice how one of the sysadmin-inc.com servers even says ns1.sysadmin-inc.com is 209.16.228.150. This is all caused, of course, by ns1.sysadmin-inc.com being used to register domains (whois -h whois.networksolutions.com "host ns1.sysadmin-inc.com" and whois -h whois.networksolutions.com "server ns73505-hst"). It seems few people realize that when they register a nameserver with Internic, the root servers get their own A record for that host. This is why it's a bad idea to use normal machine names for domain registration and, on the flip side, a bad idea to use nameserver names for normal machine tasks. Hope this helps. -- Dan Peterson <danp@danp.net> http://danp.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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