How do I block traffic from an entire country?

Saw a 60 minutes show today where known hackers in Russia were not punished, but considered heroes by the community for ripping off the evil Americans. 

 

I am not interested in any traffic from such a country.  How do I configure NIS to block everthing from Russia.

 

Also, does anyone suggest any other countries without rule of law that I could add to the [Removed] list?

 

thanks very much,

 

 

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