For linux users, you can directly use your mirror sites to download.
ex: In debian type
# apt-get install nmap
Wanna do something crazy ?
check your current public IP. click here
and type this in your terminal. ( If you are using Windows cmd, type in cmd )
you have to change 192.168.1.0 to your subnetwork address (you can get it from your public IP) and give the range as 255.
If there is no error, the scan should start.
It will show all the public IPs within the range which are up.
