short, two part question ICANN Vs. The World

[stovetop 202 <stovetop_202 () yahoo com>]

Topic: ICANN Vs. The World.

The question at hand is.. Do countries/businesses have to affiliate or utilize any of those services provided by ICANN 
other than the assignment of an IP address?  And can you get away with LAN/CAN/MAN stand-alone systems [instead of 
utilizing DNS-via-ICANN]??
Example: 
Is it legal to cut off those DNS systems and loop in backwards?  (instead of bidirectional).  **  I don't want my 
city/schools/other systems hooked into the World Wide Web. // someone let me know when you get a chance.