What really happens when you type in a url in the browser?
http://igoro.com/archive/what-really-happens-when-you-navigate-to-a-url/
Explanation of HTTP Protocal:
http://geekexplains.blogspot.in/2008/06/whats-http-explain-http-request-and.html
Explanation of HTTP Headers:
http://code.tutsplus.com/tutorials/http-headers-for-dummies–net-8039