1)For part-1 run python server.py and give input portnumber.
2)For part-2 run python multithreadedserver.py and give input port number,PUT/POST requests are also handled.
3)For part-3 run python client.py server_host server_port filename typeofrequest(GET or POST) [ Example : python client.py 127.0.0.1 5000 1.html GET ]
4)For part-4,we made authentication page when user opens the page first time.If the user is not present,we add the user.If he is already present,we validate his details.
5)Preventing DOS attack - If more than 10 requests come with timegap between consecutive less than 5 seconds,we block the ip address and after 1 minute the person can access the page again.