Group18_Awesome4some: HTTP/FTP Proxy servers (introduction)

Proxy servers:

A proxy server is a server (a machine or a program) which is present between the user (client side) and the Internet. When a person requests for a particular web page, the request is passed on directly to the server and the requested page is located, retrieved and sent back to the requested computer. This is done by locating the surfer’s IP address, and then transferring back to the same IP address which had requested the web page. But with the introduction of proxy servers the request is intercepted by it and the request does not reach the real server. The proxy server acts as a regular server by saving caches of all previously downloaded websites. When a request sent to server is intercepted by the proxy server, it checks in its cache. If the page is found then it is sent back to the Ip which raised the request. If it is not found then, the proxy uses its own IP address and raises a request to the real server and then sends it to the requested terminal. This is useful in terms of retaining anonymity, to speed up the process of webpage retrieval and to filter requests. There are many types of Proxy servers like transparent proxy, anonymous proxy, distorting proxy, high anonymity proxy.

Http proxy server:
Hypertext Transfer Protocol (HTTP) is an application-level protocol used for retrieving inter-linked resources led to the establishment of the World Wide Web. HTTP is a request/response standard of a client (end user) and a server (web site). The client making an HTTP request—using a web browser, etc—is referred to as the user agent. The responding server—which stores or creates resources such as HTML files and images—is called the origin server.

HTTP proxy server is a proxy, allowing working on the Internet with HTTP and (not always) FTP protocols. It (as well as other proxy servers) can carry out caching of information downloaded from the Internet. HTTP proxy servers are the most prominently used.

Ftp Proxy server:
File Transfer Protocol (FTP) is a standard network protocol used to exchange and manipulate files over an Internet. FTP is also built on a client-server architecture and utilizes separate control and data connections between the client and server applications. FTP is also often used as an application component to automatically transfer files for program internal functions and can be used with user-based password authentication or with anonymous user access.
Ftp proxy is an application level gateway for FTP. It sits between a client and a server forwarding command and data streams supporting a subset of the file transfer protocol as described in RFC 959. Beside this basic function which makes the program useful on firewall or masqueraders it offers fixing the FTP server (e.g. for connections into a protected LAN) and proxy authentication.