Originally posted here by Irongeek
What can you find out from an IP?

Here I will outline some use full Unix and NT commands for finding out more information about a given COLOR=purpleIP. Some of these techniques will fail depending on firewall rule sets.

Items to be covered:

How do I find my own IP?
How do I find out if an IP is contactable?
How do I find out what organization owns an IP?
How do I find out what OS a box is running?
How do I find out what ports are open/services are running?
How do I tell who is logged in to that box?
Any good all in one tools?
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A good *remote* all in one tool I like to use is

http://www.dnsstuff.com

Is a nice compliment to local tools.