I.P addresses can usually be traced to close to the source.

I.P are block allocated to service providers who can usually trace who was using an I.P at any one time.

Go here and it will tell you where YOU are;

http://www.geobytes.com/IpLocator.htm?GetLocation

You can find which provider it came from here;

http://samspade.org/

It is possible to Spoof an address (create a fake) which are probably impossible to trace after the event, unless you are one of the mysterious American intelligence agencies.

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