1. Write a program that requires one command-line argument that is an IPv4 dotted-decimal address.
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3. Create an IPv4 TCP socket and bind this address to the socket along with some port, say 9999.
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5. Call listen and then pause. Write a similar program that takes an IPv6 hex string as the command-line argument and creates a listening IPv6 TCP socket.
6.  Start the IPv4 program, specifying the wildcard address as the argument.
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8.  Then, go to another window and start the IPv6 program, specifying the IPv6 wildcard address as the argument. 
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10. Can you start the IPv6 program since the IPv4 program has already bound that port? Does the SO_REUSEADDR socket option make a difference?
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12. What if you start the IPv6 program first, and then try to start the IPv4 program?