Re: [Hampshire] problems with accessing startx.co.uk

On Wed, May 05, 2010 at 01:04:51PM +0100, John Lewis wrote:
> I don't understand the DNS system at all other than a need to put some
> nameservers into /etc/resolv.conf (or equivalent) and didn't realise
> until this problem came up that startx.co.uk needed the *.myth.co.uk
> servers

The DNS is, as James said, a distributed database. It primarily
contains the information for turning a domain name (e.g. startx.co.uk)
into an IP address. It can also contain a whole load of other
information, but we'll ignore that for now.

When your browser looks up startx.co.uk, it asks a nearby resolver
(the "nameserver"s specified in /etc/resolv.conf) for the address. If
the resolver doesn't have that information, it can either ask another
resolver (if that's configured, which in most cases it won't be), or
it can work its way up the name.

There are several things going on here, all of which need to be
connected up in the right way:

1) The DNS records you want to publish. In this case, the "A"
record(s) for (www.)startx.co.uk, which say "the domain name
startx.co.uk refers to this IP address".

2) The hosting of your DNS records. That is, who is responsible for
the physical machines and the DNS server software where your DNS
records live.

3) The "glue" records, held by the nameservers for the co.uk domain,
which say "For all queries about startx.co.uk, talk to these IP
addresses".

4) The ownership of the startx.co.uk domain name, which is a simple
registration of who has the right to govern the administration of
startx.co.uk.

Looking at these in reverse order:

For .co.uk domains, the registration of the domain name (i.e. part
4, above) is held and administered by Nominet. Nominet effectively
allows subcontractors to perform most of that function for them --
these subcontractors are domain name registrars, and Mark Lewis is
such a registrar. He takes your details and your money, does the
necessary paperwork, and submits it to Nominet. At that point, you are
the owner of the domain name -- but nothing else is set up yet. The
details Mark submits to Nominet go into the WHOIS database. This is
what you see when you run "whois startx.co.uk".

Once your domain name is registered to you, the technical bits
start. Your registrar (i.e. Mark) will tell the owners of the .co.uk
domain (i.e. Nominet) where to find your DNS records. This shows up
under the "name servers" section of the WHOIS database. In your case,
the name servers are hades and persephone.

This then also answers part 2 -- Mark is responsible for your DNS
hosting. It's his servers that serve up requests for your DNS records.

Finally, there's the records themselves: what IP address is
represented by "startx.co.uk" or "www.startx.co.uk"? This information
is held in your "zone files".


Now, looking at this chain of requirements, you still seem to own
the domain (from whois); you probably have glue records (as the
nameservers are shown in the whois database); the listed nameservers
are up and running (dig @hades.myth.co.uk myth.co.uk returns results).
However, your DNS records themselves are not hosted on either of the
nameservers that should be doing so.

This looks like a configuration screw-up on Mark's part (or,
rather, on the part of one of his sysadmins). Pretty much all the ways
of fixing it that I can think of involve talking to Mark at some
point.

Hugo.

PS. As an aside, it's possible to separate out most of the functions
above. For example, carfax.org.uk is registered with one company
(parts 3 and 4), hosted by Bitfolk (part 2), and I write my own zone
files for it (part 1), and push those zone files to Bitfolk's servers
automatically when I change them.

--
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PGP key: 515C238D from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
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