The internet is a huge network of computers which links many different types of computers all over the world. It is a network of networks which share a common mechanism for addressing computers, and a common set of protocols for communications between two computers on the network.

What Is HTTP ?
HTTP (Hyper Text Transfer Protocol) is a stateless protocol. It means fresh connection to the server is required for every item to be downloaded. It transfers hypertext across the internet. Clients and web servers communicate via this protocol. Following are the basic steps of this protocol.
a.    Client opens socket connection to the HTTP server, typically over port 80.
b.    Client sends HTTP request to server.
c.    Server sends back response.
d.    Server closes connection.

What is a HTTP Proxy Server ?

It is a program that acts as an interface between a client and a server. It receives requests from the clients, and forwards them to the server(s). The responses are sent back in the same way. A proxy thus acts both as a HTTP client and a server. Request from a client to a proxy server differs from normal server because the Requests in one way.
The complete URL of the source being requested must be specified because it is required by the proxy to know where to forward the request.

Important Internet Applications

1.    TELNET
2.    FILE transfer protocol (FTP)
3.    Electronic mail (Email)
4.    Gopher
5.    Internet Relay chat (IRC)
6.    Usenet News
7.    World Wide Web (WWW)