DNS resolution troubleshooting

[Scott.Wiseman]

The book is great. But it would be nice is someone helped you with the
basics. 
The book makes a great deal of sense...

DNS is a complex flat file database structure.
And for someone who knows NT, SQL, ASP, relational not flat file
databases it is a different kind of thought.
But once introduced to DNS and to Bind the program
it becomes clearer that this is an efficient and effective
system for controlling a public database...

back to the book,

Scott

-----Original Message-----
From: Kevin Darcy [mailto:kcd at daimlerchrysler.com]
Sent: Thursday, June 15, 2000 12:14 PM
To: comp-protocols-dns-bind at moderators.isc.org
Subject: Re: DNS resoltution troubelshooting


As Barry said, most of these questions are answered in the _DNS_and_BIND_
book. That would be the most thorough and complete way of learning this
stuff from scratch.

If you just want to gain a little more insight into the query resolution
process through practical examples, just try turning on "debug" and
turning off recursion in "nslookup", and resolving a few queries "the
hard way" by first sending the query to a root server (you can find the
names and addresses of the root servers by doing an "NS" query of the
root zone), and then following the referrals you get (the NS records in
the Authority parts of non-authoritative responses) until you get an
authoritative response. This mimics what a regular iterative server has
to go through to resolve the name, when it has no information to go on
other than the root hints. (Normally, of course, it has at least
_some_ information already cached, so the resolution process in practice
is not nearly so laborious).

If you have access to the "dig" utility, it tends to be better at this
kind of thing than "nslookup".


- Kevin

Shawn wrote:

> What tools / resources can I use to check / troubleshoot the DNS
> resolution process? I mean, I'd like to be able to see the DNS records
> for some domains. Is that possible? Can you see my DNS configuration
> or other peoples? How does the DNS resolution take place... When I
> type a domain name, how does it find the name servers, in what order
> and how does it resolve the name to an IP... in a more technical
> terms. Does only one of my name servers in my interNIC records need to
> work, technically for people to reach my domain? Or even if 1 of 3 of
> my listed NS were down, even the primary server, what would the
> problems be for others to resolve my domain name?
>
> I only have a basic understanding of DNS, so I am sorry if I sound
> ignorant.. I guess I am. I am trying to learn. Other than "nslookup"
> in WinNT, what can I do test and troubleshoot DNS queries and what DNS
> servers are responding to or are able to respond to my quires.. I
> guess to just see if everything is working, once I get it all setup.
>
> I've seen a few posts of people listing all the NS that either
> authoritatively or non-authoritevly respond, as well as information of
> all the NS servers listed in the zone files...  How can I do this?
>
> THANK YOU!