nslookup using localhost.0.0.0.127.in-addr.arpa as a nameserver

Wed Sep 27 19:36:57 UTC 2000

On Wed, Sep 27, 2000 at 03:16:54AM +0000, Star Night wrote:
> I think I need to make myself more clear on this. Sorry if I was not
> clear last time. I am new to DNS and excuse any blunders here.
> 
> 
> 
> This is what I have :
> I have two static IP address from my ISP
> 24.13.68.211 and
> 24.180.74.165
> and I have nothing more. I don't think my ISP even supports DNS and
> they will not.(which may mean that the reverse lookup is not going to
> work)
> 
> 
> 
> This is what I want:
> I am trying to run a web server and wants to run my own DNS servers.
> 
> 
> 
> This is what I have done:
> registered my domain which is learnfreeonline.com with internic
> with
> 24.13.68.211 ---> ash.learnfreeonline.com primary DNS server
> 24.180.74.165 --> ash2.learnfreeonline.com as the secondary name server.
> I configured DNS  on 24.13.68.211.(I have not yet put DNS on
> 24.180.74.165).
> 
> 
> 
> 
> This is what I get:
> when use nslookup from 24.13.68.211 (according to one of the books I
> read about DNS , if the DNS server is set up correctly then
> when I do nsllokup it should use ash.learnfreeonline.com as the default
> server)
> the server defaults to localhost.0.0.0127.in-addr.arpa as the server.
> I can resolve a internal host and I can resolve an external host(e.g:
> abc.com).
> But when I tried to query my domain from my another naime server(from
> myISP) using nslookup, the resolve failed.
> i.e on my ISP nameserver   nslookup learnfreeonline fails. I guess this
> means that access to www.leranfreeonline.com from outside world will
> fail.
> 
> 
> questions:
> 1. why is the nslookup from 24.13.68.211 not using
> ash.leranfreeonline.com as the dault server.
> 2. why is my ISP nameserver not able to resolve learnfreeonline.com
> 
> I can provide my db files and config file if required.
> 
> thanks
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> In article <39D11A8A.AC331CD at daimlerchrysler.com>,
>   Kevin Darcy <kcd at daimlerchrysler.com> wrote:
> >
> > The name shown for the nameserver ultimately doesn't matter much as
> long
> > as the queries are going to the right address. Apparently the address
> of
> > whatever nameserver your resolver is using reverse-maps back to the
> name
> > "0.0.0.127.in-addr.arpa". If you want that to map back to something
> more
> > reasonable, then you need to set up the appropriate reverse zone
> files. It
> > is not strictly necessary to be delegated the reverse domain, as long
> as
> > all of the servers which need to answer for the reverse zone(s)
> internally
> > are explicitly configured with it. If you have a *lot* of internal
> > servers, which would make explicit configuration difficult to
> maintain, or
> > wish to provide this reverse-zone information to the Internet, then
> you
> > would need to be delegated the reverse domain.
> >
> > - Kevin
> >
> > Star Night wrote:
> >
> > > Hi
> > > I recently set up my DNS servers. my domain is registered. But
> nslookup
> > > deafults to using 0.0.0.127.in-addr.arpa as the default name
> server. I
> > > have two static IP's and using them for my primary & secondary name
> > > servers. the lookups of internal and external hosts works fine with
> > > 0.0.0.127.in-addr.arpa. But I am wondering why its not using my
> > > primary server(say xxx.domain.com). Does reverse lookup needs to be
> in
> > > place before name server is operational. I can provide with more
> > > information.
> > >
> > > The reverse lookup is is not delegated. Will this cause any
> problems?
> > > Also outside name servers are not able to lookup my domain.

First, some background.

The address "127.0.0.1" refers to your local host.  That is, whatever
server you're on.

You should have your DNS set up so that when you look up "localhost"
from your domain [whatever that domain might be], it returns 127.0.0.1.

You should have your DNS set up so that when you try to do a reverse
DNS lookup on "127.0.0.1", it returns either "localhost." or
"localhost" followed by a your domain name.  Another way of talking
about the same lookup is to say that you are looking up a PTR record
for "1.0.0.127.in-addr.arpa."  Depending on how you are mistyping the
subject line of this message, you either have "localhost" [no dot] or
"localhost.0" on the right-hand side [RHS] of the PTR record in your
0.0.127.in-addr.arpa zone file.  You should have "localhost." [with the
dot] on the RHS of that record.

And, as the Bard would have said were he ansering this message, a rose
by any other name still serves names.  Does it really matter whether
'nslookup' calls your machine localhost, localhost.learnfreeonline.com,
or ash.learnfreeonline.com?  It is ALL THE SAME MACHINE.

ANSWER TO 1.:  It is.  It is just using a different name.

You control resolution via /etc/resolv.conf.  [This is a separate
process from serving names, which is controlled by /etc/named.conf.]
If you are really anxious to have ash in there, put its IP address in
there as a nameserver.

ANSWER TO 2.:
Systems such as your ISP's name server only know what they have been
configured to know, plus what they are told by other name servers.  The
".com" name server had to have told them who your domain's name servers
are, before they could know.

I don't know what they showed before.  Now they show:

learnfreeonline.com	nameserver = ASH.learnfreeonline.com
learnfreeonline.com	nameserver = ASH2.learnfreeonline.com

Authoritative answers can be found from:
learnfreeonline.com	nameserver = ASH.learnfreeonline.com
learnfreeonline.com	nameserver = ASH2.learnfreeonline.com
ASH.learnfreeonline.com	internet address = 24.13.68.211
ASH2.learnfreeonline.com	internet address = 24.180.74.165

HOWEVER:

*** No address information is available for "www.learnfreeonline.com"

Check your 'syslog' output for errors when loading this domain.

If you are behind a firewall, you will need to open a hole for this
domain.  This is a very bad idea.  It would be better if you had an
internal name server and an external name server, and a proxy at the
firewall.  You do appear to be behind a firewall: a 'traceroute' shows:

...
10  cr1.avnl1.nj.home.net (24.3.128.62)  11.940 ms  12.611 ms  11.720 ms
11  cc325178-b.avnl1.nj.home.com (24.180.74.165)  117.119 ms *  91.268 ms
12  * * *
13  * * *
14  * * *
15  * * *
...

Or is @Home just continuing to be a bad netizen by blocking any queries
going in to a subscriber's site?

-- 
Joe Yao				jsdy at cospo.osis.gov - Joseph S. D. Yao
COSPO/OSIS Computer Support					EMT-B
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