Peter Brezny <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]> http://danp.net
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