Given a specific network number I want to find out who owns it (or more 
specifically who it has been assigned to). I have used all the regular dns 
tool (nslookup,dig, whois etc). It would appear that the network number I 
am looking for has been assigned but has no dns servers associated with it 
and hence I get no hostname resolution or authority information, but can 
ping hosts.
Well I got a fair number of replies however as suspected there really is no 
magic oracle to give you this sort of information. Basically you need to 
make use of the tools available to get as far down the DNS chain as 
possible ending possible with an enquiry at the ISP. The first thing to try 
is to use the various DNS tools as follows :-
nslookup  (come as part of the bind distribution 
dig
generally these will only be usefull if the address you are looking for is 
registered with in the DNS (no always the case). In my case the address's 
were allocated and routed by doing a nslookup produced an unresolved 
response.
whois      http://ds.internic.net/wp/nwhois.html
           http://www.ripe.net/db/whois.html
           http://www.ripe.net/nicdb.html
           http://www.parked.com/whois.htm 
           telnet://rs.internic.net (whois 193.128.218 = derwent
also usefull for name searched e.g. derwent
           http://www.ripe.net/db/dbwais.html
The above may or may not provide you with information you are after, blocks 
of address are assigned from the central authorities e.g. ripe & nic to 
naming registries e.g. ISP's who will then allocate address's to various 
customers. In my situation I was looking for details on a network address 
which I had been told was assigned to us e.g. derwent but in actual fact it 
belonged to our parent company Thompson publishing who then allocated it to 
our US offices. 
If the above tools don't come up with anything you can use the tool 
traceroute which shoul give you an indication of which ISP or last point of 
contact is passed through before reaching the address in question so for 
example :
traceroute  www.derwent.co.uk 
will hit a pipex gateway who are one of our ISP's I could then enquire with 
pipex (whether they would provide you details such as IP assignemnets I 
don't know).
Its all a bit like trying to find which customer received a particular 
product of a manufactured batch. The maufacture (e.g. internic) sells to a 
wholesaler/retailer (ISP) who then sells to the end customer. Obviously the 
manufacturer dosn't necessarily know who its end customers, it depends on 
whether it sells direct or whether the retailer reports back who it sold 
to.
Given a little time and effort and using the above methods you should be 
able to find the info you want
Many Thanks to all those people who replied to my original query.
     
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*                                                                        *
* Stuart Burch                      Derwent Information Publishing       *
* (System Administrator/Developer)  14 Great Queens Street               *
*                                   London                               *
* Group Business Development        WC2B 5DF.                            *
*                                                                        *
* Email: sburch@derwent.co.uk       Tel: 0171-344 2800 x 3001            *
*                                                                        *
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