DNS Question

[Jay Bollyn]

We are using private IP addresses on our Intranet. For outbound traffic to the Internet, the router assigns 66.99.13.253.

We pay a subscription fee to a remote database vendor. This vendor authenticates our requests by IP address range. (If the request is recognized as being from domain neiu.edu, then access to the database is granted.)

The DNS servers used by the vendor do not recognize 66.99.13.253 as one of ours. Their DNS servers are listed as the Authority for PTR records in the address range 66.99.13.0/24.

The suggested solution is to have their DNS Administrator make a change to their servers that points to our DNS servers as the Authoritative source for these PTR records.

Is there any way I can tell if this has been done? Is there a utility like nslookup, where I can specify the particular DNS server to be used?

Thanks for any info.

Of course, points assigned.

:-) Jay

[Ron Kinner · Accepted solution]

nslookup will work.

nslookup
server YourDNS


for other options type:

?

Ron

[Jay Bollyn]

Thanks Ron,

Previously, I was confused about the subcommand syntax. I was trying to do things like...

nslookup /?

...which was just not helpful.

Also, I really need to find a two-page online primer, 'what every network admin needs to know about DNS.' (I should be able to google this.)

:-) Jay

[Ron Kinner]

This is the book I use.

http://www.oreilly.com/catalog/dns4/index.html

I don't remember paying anything like the price they quote here so I may have got the 3rd edition on sale.

Ron

[Jay Bollyn]

I agree, O'Reilly does a good job explaining IT topics. I have a few of their titles in my personal collection. If we do not have this title in our library collection at work, I will order it.

:-) Jay

[Jay Bollyn]

So here is a simple DNS situation which I cannot explain:

Our main University IP address is 66.99.13.58. When I enter this IP addr in nslookup at work (using our DNS server 66.99.13.51) I get www.neiu.edu, as expected.

When I enter 66.99.13.58 in nslookup at home, using the DNS server for attbi.com (63.240.76.4), I get:

*** ns6.attbi.com can't find 66.99.13.58: Server failed

Yet when I enter 66.99.13.58 in the IE address bar at home, it displays our NEIU home page.

I'm sure there is a simple DNS explanation for this conundrum.

:-) Jay

[Ganesh Babu]

Jay,
From your home do u wanna try

nslookup www.neiu.edu

and see what is the result u get??

Ganesh

[Jay Bollyn]

Ganesh,

From home, when I enter www.neiu.edu into nslookup, I get the 'non-authoritative answer' 66.99.13.58. I believe this means my home DNS server is giving me this IP addr from its cache.

From home, when I enter the following at the nslookup prompt:

> www.neiu.edu 66.99.13.51

...I get 66.99.13.58 as the (understood) 'authoritative answer', since 66.99.13.51 is listed as the Authority for the address in question.

:-) Jay

[Ganesh Babu]

so what is the problem now??

:)

Ganesh

[Jay Bollyn]

I am going to post my follow-on question in HP-UX Networking, since I think that is the more appropriate Forum for DNS / bind issues.

As it turns out, I already had 'DNS and Bind, 4th Ed.' on CD-ROM, as part of 'The Networking CD Bookshelf, Version 2' from O'Reilly. There are 7 books on this CD-ROM. I think every network admin needs this title in his office.

:-) Jay