New to this: How to map network?

[arieldoucette () netscape net (Ariel Doucette)]

Hi,
I am relatively new to the security / networking world.
Is there a command or application (free?) that will map out my network at work? I want to find all of the IP's of the 
routers and computers on the network.
Is this possible, or do I have to go around the office with a pen and paper?
Thanks

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