HTTP Response

The server returns a response which begins with a status code number, such as 404: Page Not Found, and 200: OK.
There are 40 defined status codes.
The response can also include any number of response headers

Accept-Ranges:	Server specifies its acceptance of range (parts of a file) requests. `Accept-Ranges: bytes`.
Age:	Time since the response was generated by the server. Useful for changing data such as weather and stock quotes. Age is in seconds. `Age: 600`
ETag:	Value of the entity tag for the requested variant. ETags are meant to function as unique identifiers for documents.
Location:	Used to re-direct the user to another location. `Location: http://www.w3.org/pub/WWW/People.html`
Server:	Information about the server. `Server: CERN/3.0 libwww/2.17`