[lug] DNS, named and RH6.1

[rm at mamma.varadinet.de]

On Sat, Jul 15, 2000 at 08:40:08PM -0600, Nate Duehr wrote:
> Hi John, 

> [...]

> The issue with the @ in your zone file is an ORIGIN statement problem.
> That appears to be the cause of the double ajstarkey.com.ajstarkey.com.

domain.com.domain.com problems most often occur because of a missing
dot '.' at the end of an entry in your zone file.

host.my-domain.com.
another.my.domain.com
                     ^ 
		     There should be a dot here!
In the second case the server will append the default zone name (@)
and you end up with what seems to be the problem.

> On Sat, Jul 15, 2000 at 12:45:03PM -0600, John Starkey wrote:
> > Hi all again.
> > 
> > I'm trying to set up a caching DNS for the experience of doing it, more
> > better pay maybe? :}
> > 
> > I am a little confused about the sequence of events. Here's what I see as
> > happening, could someone correct me if I'm wrong?
> > 
> > #nslookup ajstarkey.com
> > 
> > the kernel looks at /etc/resolv.conf and finds 

The resolver (library code) does this.
 
> > search ajstarkey.com

here you set a default zone. This zone will be appended
whenever you search for something that is not a FQDN.

> > nameserver	192.168.0.2 
> > nameserver	205.139.34.25
> > nameserver	205.139.34.24
> > 
> > then looks for the 192.168.0 in /etc/named.conf, 

what is 'it'? The resolver won't touch your named.conf.
If you configured it to use nameservers first then it'll
go and ask the first server in your list of nameservers
(192.168.0.2). If you set it up to first consult files
(this can be set in /etc/nsswitch.conf) than it'll check
the file /etc/hosts.

> > finds it then looks for
> > 192.168.0 (using reverse DNS) and finds 0.168.192.in-addr.arpa which
> > refers to /var/named/named.192.168.0. Now does it look at
> > the 
> > 
> > 	NS	 ajstarkey.com
> > 	
> > record in the file? 

I think you are mixing up Bind actions (server side)
and resolver actions (library side). Use 'strace' on your
program (nslookup) to see the difference.

> >I thought it would look at the SOA at the top, which
> > is ns.hughes.net, and be shipped off to that domain to check out that DNS
> > before climbing back up the tree. I could swear it does, which might explain 
> > the result of 

Backreference:

> > 	NS	 ajstarkey.com
                              ^
			      No dot here. So the resolver will
			      append ajstarkey.com to it! If this
			      isn't found in /etc/hosts it'll ask
			      the name server for ajstarkey.com.ajstarkey.com

> > 
> > ajstarkey.com.ajstarkey.com
> > 207.138.82.242
> > 
> > Before I started using "@" in place of ajstarkey.com in the
> > 
> > ajstarkey.com		A	207.139.82.242
> > 
> > record. Which returns:
> > 
> > ajstarkey.com
> > 207.138.82.242
> > 
> > [snip]

> > I hope this is clear enough. It's the weekend I don't expect anyone to
> > spend an hour commenting. I played around with this (and d-loading Oracle
> > with my soon to be obsolete 56k) for 20 hours yesterday. (I settled for
> > Sybase til TCI shows up.)

But this is the only time one can spend an hour or two ;-)
I think you confuse yourself by not making a difference between
the nameserver and it's configuration files and the code an application
calls to look up host names (on linux/unix this is a dynamically loaded
library).

If you have more specific questions feel free to send me more
mail. I'll pick up my copy of 'Bind' (highly recomended btw.) 
over tea break and bring it with me, just in case ...

 Ralf