ok easy
http://www.arin.net/whois/index.html
type the IP in and go ...
if the ARIN dot has this IP ... he will show u a other url to make the whois request
i u working on a unix box or u have access to it
type
whois -h whois.thur.de 123.123.123.123
(123.123.123.123) for the IP ...
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