[lug] DNS and a thanks for the DSL info.
rm at mamma.varadinet.de
rm at mamma.varadinet.de
Sun Aug 27 10:11:41 MDT 2000
On Sun, Aug 27, 2000 at 11:10:21AM -0400, John Starkey wrote:
> > DNS is subtle and quick to anger.
True, true ...
> Does this mean I will neeed to rely on them to enter my records?? That's
> what I was trying to avoid in the first place. This may be a warped view,
> what I wanted to do was have one entry at register.com for backup. Then
> make mine the primary.
Well, that depends on the size ouf your IP-address range. While the
IP space is numeric, the DNS namespace is a tree-shaped space of
strings. When revers mapping was introduced the clever idea (tm)
of mapping on space onto the other was:
take the IP-Address as expressed in qaudruples and split it up
192.168.2.1 => 192 168 2 1
take away the 'Host' parts
192 168 2 1 => 192 168 2 (attention: this works only if your netmask uses a
multiple of 8, i.e. is a class A/B/C net)
reverse these 'strings' and append 'inet-addr.arpa.' to it.
192 168 2 => '2.168.192.inet-addr.arpa.'
This is what gets looked up if you look up an IP address.
So, technically speaking one can only set up a SOA for a class A/B/C
network. There are clever workarrounds for this (have a look at the
bind-book) but they all involve some sort of work on the side of the
'owner' of the IP-range you happen to live in.
> I think I may be confused about the purpose of reverse. Is it only for
> entering IP@ instead of alpha-numeric??
> And forward would be for entering
> the alpha-numeric and assigning IP@ within??
Forwarding means: go ask someone else ;-)
> So when I do:
nslookup can do both: use the resolver (which is a system library, _not_
a server!) or directly ask a server. In 'nslookup' you can set the
server that gets asked with:
> It tells me the localhost addy and the name of the server. But tells me
> the server is returning an error. So how do i start the server?? Maybe
> this is the /usr/sbin/ndc (the resolver??) and named (the server, based on
> the d at the end). I just scrolled down and saw that you state this later,
> but ndc??
depends on the server you want to run. I use bind and start that service
from an init script. But the exact workings of this depend on the distribution
> > search example.com
> > nameserver 127.0.0.1
> So does the "nameserver 127.0.0.1" have an RR or is this just something
> that resolv knows to look for and where?
> > Now look in /var/log/messages to make sure there aren't any errors:
> > guin:named# tail /var/log/messages
> > [...]
> > Aug 27 00:10:49 guin named: reloading nameserver
> > Aug 27 00:10:50 guin named: master zone "example.com" (IN) loaded
> > (serial 2000082700)
> > Aug 27 00:10:50 guin named: Forwarding source address is
> > [0.0.0.0].1223
> > Aug 27 00:10:50 guin named: Ready to answer queries.
> > guin:named#
> This is one I never see. Using "restart" I get the [ok] [ok] but never any
> entries in messages.
You might need to set the debuglevel of you bind (named) to a higher level
(by sending a SIGUS1 to the server process).
> > As an experiment, you can set up records for "example.com" just as I did
> > above (example.com is allocated for use as an example).
> So you actually set up these records on your machine?? I'll try them. I've
> used three different books and the HOWTO and tried all the simple examples
> I could find.
> > I don't know why your setup wasn't working, but my first guess is: Did you
> > actually use "serial" in the SOA record, or did you put a real number in
> > those fields? It should look something like my SOA above.
> No, that was just some shorthand. I remembered the entries but not the
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