Web Proxy and Know How It Works

In computer networks, a proxy server (a computer system or application program) that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as file, connection, web page, or other resource, available from a different server. Proxy Server evaluates the request according to filtering rules.

For example, it may filter traffic by IP address or protocol. If the request is validated by the filter, the proxy provides the resource by connecting to the relevant server and requesting the service on behalf of clients. A proxy server may optionally alter the client requests or server responses, and sometimes it may serve the request without contacting the specified server. In this case, 'caches' responses from the remote server, and then return a request for the same content directly.

A proxy server has many potential purposes, including:
  • To keep the engine from the interference of people (mainly for security)
  • To speed up access to resources (using caching). Web proxies are commonly used to cache web     pages from web server
  • To implement the policy of access to network services or content, for example, to block unwanted sites.
  • To log / audit usage, namely employees of the company to report the use of the internet.
  • To bypass the security / parental control.
  • To scan for malware transmitted the content prior to delivery.
  • To scan outbound content, for example, data leakage protection.
  • To avoid regional restrictions.

A proxy server that passes requests and replies unmodified is usually called a gateway or sometimes tunneling proxy. A proxy server can be placed on the user's local computer or at various points between the user and the destination servers on the Internet. A reverse proxy is used as a front-end to control and protect access to the server on a private network, usually also perform tasks such as load-balancing, authentication, decryption or caching.

Type and Function Proxy Server
Proxy Server has one or more of the following functions:

Caching proxy server
A caching proxy server accelerates service in demand by taking the content is stored from a previous request made by the same client or even other clients. Caching proxies keep local copies according to the requested resources, allowing large organizations to significantly reduce bandwidth usage and costs, while significantly increasing performance of computer networks. Most ISPs and large companies have a caching proxy. This machine is designed to provide file system performance is superb (often with RAID and journaling) and also contain hot-rodded versions of TCP. Caching proxies were the first kind of proxy server.

Some evil-caching proxy has a weakness (eg, inability to use user authentication). Some of the problems described in RFC 3143 (HTTP Proxy Found problem / Caching).

Other interest in the use of proxy servers is to reduce hardware costs. An organization may have many systems on the same network or under control of a single server, prohibiting the possibility of an individual connects to the Internet for each system. In such cases, individual systems can be connected to one proxy server, and proxy servers are connected to the main server.

Web proxy

A proxy that focuses on the World Wide Web traffic is called a "web proxy". The most frequently used web proxy is to serve as a web cache. Most of the proxy program provides a way to deny access to the URL specified in the blacklist, thus providing content filtering. It is often used in corporate, education or library environment, and other places where the desired content filtering. Some web proxies reformat web pages for a particular purpose or audience, such as for mobile phones and PDAs.

AOL dialup customers used to choose their requests routed through an extensible proxy 'narrowed down' or reduce the detail images in JPEG format. This speeds up performance but caused problems, either when the resolution is needed or when a program is reduced yield incorrect results. This is why in the early days of the web many web pages contain a link saying "AOL Users Click 'to go through a web proxy and to avoid bugs in the software is weakened.

In general it can be done by a proxy server such as:
 
Can make it look like we are surfing from another country, another ISP, just no other word. This term is known as the "Hide IP". How it works is this:

Subscribe to our computer IP 168.192.1.17Kita NET ISP in the image that was in Yogyakarta Indonesia and URL citra.net.id

So that would be read later is: 168.192.1.17.citra.net.id, if we use a URL proxy from other countries such as IP 69.217.73.52 proxy, IP is owned by the United States. So that read later is 168.192.1.17.69.217.73.52. The result is as if we are browsing from the U.S. but in Yogyakarta. Even if we use URL the result is 168.192.1.17.ninjaproxy.com.

Accelerate Internet Connection. Proxy server charge of storing the pages on the Internet that have been in open which we will refer to a cache. So if there are client request and the page has been cached, Proxy server will immediately respond to that page and send it to the client as if it were the public IP. The result was a fast internet connection. But if the page had never been cached, then it must come out first to a public IP website in question and the connection is slow.

The proxy server can do:

Hiding Client

The main security feature is a hidden proxy server client. Such as Network Address Translation, proxy servers can make the entire internal network appears as one machine from the Internet because only one machine which passes the request to the Internet.

Such as Network Address Translation, proxy server prevents external hosts to access services on internal machines. In the proxy server, there is no routing to the client because the domain address internal and external network may not be compatible and because there are no transport layer routing between both networks. Proxies do this by updating the feature request, instead of replacing and re-calculate the address header. For example, when a client makes a request through a proxy server, proxy server receives the request as if the destination web server on the internal network. He then update request to the external network as ordinary web browser. At the time the proxy receives the response from the actual web server, it responds to the internal client. Only HTTP is passed through a proxy, rather than TCP or IP. TCP / IP (and other low-level protocol) is updated by proxy; they will not be passed through the proxy.

Another aspect of concealment is the deployment of client connections; proxy server can be used to share one Internet connection and IP address to the entire network. Therefore, the WinGate proxy server such as very popular in home and small office environments where there is only one connection or a dedicated dial-up available.

Tags: What is a proxy, How the proxy, proxy Uses, Benefits proxy, the Proxy, Proxy Server

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