[lug] DNS and a thanks for the DSL info.

rm at mamma.varadinet.de rm at mamma.varadinet.de
Sun Aug 27 11:43:13 MDT 2000

On Sun, Aug 27, 2000 at 11:34:46AM -0600, Sean Reifschneider wrote:
> On Sun, Aug 27, 2000 at 06:11:41PM +0200, rm at mamma.varadinet.de wrote:
> > take the IP-Address as expressed in qaudruples and split it up
> > =>  192  168  2  1
> >
> > take away the 'Host' parts
> You don't drop the host part if you're looking up the address...  You only
> drop that when searching for an authority.  So, given
>, your resolver would first try looking that up,
> then would start looking for 2.168.192.in-addr.arpa, 168.192.in-addr.arpa,
> until it found somone who knew where to get those records.

Yes, of course (too early for me ...)

> > 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)
> That's because DNS can't really search for all possible combinations of
> what an unusual mapping might be.  It just drops components until it finds
> somone who will resolve the domain.
> So, if you have a /28, your ISP *SHOULD* be able to delegate your
> records to your server using a trick.  Otherwise you have to get your
> ISP to deal with reverse DNS changes.

My point. But is there an easy way for the ISP to do that? The only
way i know off would be to delegate every single address within the range
to you. But this is exactly what Dave wanted to avoid.

> > 192 168 2 => '2.168.192.inet-addr.arpa.'
> I think you mean "in-addr.arpa".

Yes. Haven't written them for quite a while.
Thank's for the corrections


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