Re: IP address allocation

[Edward Rustin <ed () well com>]

IP Allocation has nothing to do with which IPs are being used.

What the IP allocation from ARIN/RIPE/APNIC/LANIC does is give you right
to use those IP addresses which should (in theory) be routable to you
(depending of course on things like who your internet provider is).

To use your example. Say I'm allocated the the IP block 200.0.0.8 through
200.0.0.15 and that I've been allocated them by RIPE via my ISP (RIPE and
ARIN will only deal directly with you if you need a /20 or greater,
otherwise you're expected to request the block through your ISP). From the
point that I've been allocated this IP block then anyone that puts those
IPs into the whois databases at RIPE will get my details back.

This is the right thing (even if I'm not useing any of those IPs) because
for a set period of time those IPs are my 'property' they are not IPs that
are available for anyone to use. They are there for me.

I'm not sure but I think that you are confusing this with the DNS
system.

However all the DNS system does is to translate a domain name
"sillyness.com" into an IP address. Once again this has nothing to do with
that IP address being used or not (although it would be a bit silly to
have a domain pointing at an unused IP address). This also has nothing to
do with IP allocations. You could happily register a domain name and point
it at an IP address that isn't owned or controlled by you

But also with the DNS records, if the record exists then people can see
the information within it regardless of the IP address it points at being
active or not.

I hope this answered your query.

Edward Rustin

Director of Security, Onlineguardians.org
Support Analyst, Get Plc


On Thu, 31 Jul 2003, Terry wrote:

> Hi,
>
> I've googled but haven't really come across anything that answers my
> questions.  Is it common practice for ISPs to allocate a block of
> addresses to a customer and put in DNS records for ones that are
> unused?
>
> For example, xxx.8-xxx.15 is assigned to the customer.  Customer uses
> xxx.9 for the router and xxx.10 for web server.  xxx.11-14 are unused.
> I would expect to see DNS records for xxx.9 and xxx.10 but not for the
> rest of the block.  Am I wrong?  If there are DNS records for the rest
> of the IPs, why is that?  Is there some security reason for doing
> this?
>
> --
> Regards,
> Terry
>
>
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