title: What is machine config in asp.net
body: <p>Hai , </p>
  
  <p>I am doing a web project in asp.net. Now I am trying to keep each connection string for each user . And the user can decide which server he prefer. How to change this dynamically and where can I store this?. I happen heard about machine.config .Unfortunately i am not familiar with this. Can you just tell what it is and it's use. If any disadvantages please tell.
      And How it use?</p>