If I have an IP adress, how can I know who it is or where is it from?

Hello tito-ga!

As you have probably discovered, an IP address is a unique number
assigned to a node (computer) on the Internet.

What is a bit more difficult is trying to track down exactly who
belongs to that IP address.  In many cases IP addresses are handed out
'dynamically' as a person logs onto a dialup account, or connects to
their broadband provider.  In other words, tracing an IP address to an
individual is rather difficult if not impossible in many cases. 
However, finding out where it is from is slightly easier.

Your first step is to lookup and see who the IP address is registered
to.  DSLreports.com has an excellent 'whois' utility that will tell
you exactly who belongs to an IP address.  In many cases it will
report back the name of the ISP, which is usually enough to get the
ball rolling in an abuse case.  You can find the whois utility here :

[ http://www.dslreports.com/whois ]

You then simply type in the IP address and it will report back the
registered information.  Usually it's enough to get a good idea.  This
utility will also tell you who is registered to a particular domain
name.

Another way to search the geographic location of an IP address is
through conducting a 'trace route.'  The Internet is a packet switched
network, which means packets of data are routed from one place to the
other through a number of points on the network.  These 'routers' take
the data packets and shoot them to other routers until they reach
their destination.  Think of it like the Interstate highway system: 
Connecticut is not directly connected by road to Montana, but you can
route yourself through a number of roads to get there.  A Traceroute
utility will show you the route your data packets took to get to their
destination.  Many times if the whois doesn't help you determine the
source of the IP address in question, the traceroute will show you a
node or two above which may be able to help you track down abuse.

Since I don't know what operating system you are running, I can
suggest a web-based utility to trace the route.  I like the free,
web-based visualroute which will trace the route graphically against a
world map.  This particular utility will originate your packets in
Virginia.

Like the DSL reports Whois, simply type in the IP address to start:

[ http://visualroute.visualware.com/ ] 

You can also find a list of text based traceroute utilities at this
traceroute.org, although note that not all of them are working:

[ http://www.traceroute.org/#USA ]


Finally, you may want to inquire with your Internet service provider
if you're being attacked from a particular address.  It is often in
the ISP's interest to hault attacks on their system to prevent other
customers from losing service.

Good luck!

NishkaGA

hello! if you want to know whats your ip go to this url:

http://www.ask.com/main/followup.asp?qcat=tech&ask=Tracing+Ip&qsrc=56&o=0&snp=jeeves&qid=2AF3E8F8432AF94E820B5B3C5AF20764&dt=020505151427&back=meta%3D1%26site_name%3D%26origin%3D0%26ask%3DTracing%2BIp%26qsource%3D56%26rspick%3Drs&qcatid=45&score=0.72&aj_ques=snapshot%3DJeeves%26kbid%3D1370791&aj_logid=2AF3E8F8432AF94E820B5B3C5AF20764&aj_rank=1&aj_score=0.72

Its very long so you should copy and paste it. 
Thats all, I hope it helps!

And then there's IPv6.  Since IPv6 IP addresses are registered using a
different system, it will be interesting to see how easy it is to use
similar methods to track IPv6 IP addres.

or much sipler
http:/www.whatismyip.com

The <a href="http://www.networldmap.com">Net World Map</a> will give
you an guestimate of the geographic location of an IP address.  Go <a
href="http://www.networldmap.com/TryIt.htm">here</a> to look up an IP.

You may like:
http://www.samspade.org
http://geektools.com
http://combat.uxn.com

Hello.

Actually tracking down the real IP owner with dynamic IP addressing IS
possible. The thing is that the investigator only needs to know the IP
address of the node and the exact DATE/TIME of the IP communication.
Then the ISP may look up their logs and tell _to_which_login_ this
particular IP was assigned at that particular moment of time. Also,
the phone company has logs and they may tell you what phone number the
call originated from. Of course, there's no way telling who was
sitting at the particular computer at that particular time. :-)

There's only left to add that this kind of information would be only
available with court order in many countries for it reveals personal
information.

Good luck!