On Fri, Nov 23, 2001 at 10:22:34PM -0800, Harry Putnam wrote:
> Dave, sorry to break in with a bone head question.
Nothing is bone-headed except not asking. Not a problem.
> I was tickled to see a readable description of what some of these
> terms mean. I've run into them many times and have never really known
> what was what.
First, a recommendation, if you want to really understand this stuff.
I've been diddling this stuff since the mid-80's. I WISH I'd had
something to read other than source code and RFC's. Today, you're lucky--
you do. The book to get is "DNS and BIND, Fourth Edition", Paul Albitz
& Cricket Liu, O'Reilly (of course. In general, the O'Reilly books are
the cat's meow for comptech.)
> Your account here with a clear example provided is a nice little
> tutorial where one can see what they mean and how they work. Many
> thanks for filling that hole for me.
Glad it helped.
> Now the bone head part: What are zone files and what role do they
> play in dns lookups?
Zone files are the meat of the meal (apologies to any veggies reading
this.) They actually contain all the records that describe a domain or
subdomain--the SOA (Start of Authority), NS (NameServer), A, MX, CNAME
(all described in that earlier post), etc. These, in aggregate, are what
provide all* the information about a domain for DNS. For simple domains,
one zone file can, and usually does, contain the whole enchilada.
For more complex domains, a hierarchy of zone files are created to
handle subdomains.
[* OK, I'm simplifying slightly. There are PTR records that provide
reverse-lookup; these are kept in separate files on a per-network
basis. They're decreasingly useful in this age of DSL and cable
providers, some apologists' opinions notwithstanding. They don't
directly affect DNS forward references, you probably can't create
or manage them unless you own your own network addresses, and in
general they're fodder for a different discussion.]
The file "named.conf" is where it all starts--usually it's in /etc,
sometimes people will create a subdirectory somewhere for it (e.g.,
one site I work with created "/etc/namedb"). Look for where the named
daemon is started--that'll point you to the config file. On Redhat, this
would be /etc/rc.d/init.d/named, which is the base linked to from all the
'rc' directories. But this isn't about the System V init process...)
This file does handle global behavior of named--for instance, it tells
'named' where to find its zone files--but it is concerned primarily
with security and permissions. As such, it doesn't provide any DNS zone
information per se, but it _does_ enumerate the domains served by this
nameserver, whether it's a primary or secondary, and the location and
name of the zone files associated with the domain.
SO, to explore your DNS configuration, look first at /etc/named.conf.
Follow the pointer for your domain to find its zone file; then read
through that to see what's what.
Hope this helps some more. Get the O'Reilly book--it should be on
everyone's bookshelf who hopes to set up DNS, or even to just understand
what's going on! (In fact, I just noticed that my copy is out of date--
third edition--time to update.)
Cheers,
--
Dave Ihnat
[EMAIL PROTECTED]
_______________________________________________
Redhat-list mailing list
[EMAIL PROTECTED]
https://listman.redhat.com/mailman/listinfo/redhat-list
