What is Proxy Server

Proxy Server Basic concept 

Proxy servers are used to configure Internet connection settings. Proxy servers enhance the security for the user accessing the Internet and speeds up the Internet access by storing Web pages on the server. A client connected through a proxy server sends a request for a connection, file or other resources provided by other servers, the proxy server then responds to the clients request by either connecting to the specified server or by providing the resources present within the cache of the Proxy server. 

Internet access passes through Proxy server on the network. Proxy server accepts the Web page request from web browser (Internet Explorer) and connects Web resources on behalf of the client, gets the information, and forwards the o the information to the client. The main purpose of a proxy server is to hide computers in an internal network from outside networks. Proxy server translates the TCP port number to another port number. proxy server receives and transmits encapsulated packets from specific applications. Thus, all the application interaction such as e-mail clients must be aware of the proxy server. For example, by default, HTTP uses TCP port 80, but we can change the proxy server to accept certain TCP port numbers, like port 88 for HTTP requests from clients. When the proxy server receives HTTP requests, it would change the client system's IP address to its own, change the port back to 80, and then send the request out to the Internet. A proxy server can cache requests from users, and reduces the network traffic. For example, every user accesses few web sites frequently. Proxy servers can hold the information from user requests for a specified amount of time, eliminating the need to access that information from the remote site again to save internet bandwidth. Proxy server can also be used to filter requests which further secure a network by limiting its users to access certain web sites and internet resources. For example, you can use a proxy server to block certain web sites (like mail.yahoo.com and gmail.com) if found employees from a company spend most of their working hours for e-mail checking.
Proxy Server Showing in Picture

Proxy Server

What are the Advantages of proxy server

Server Caching - Caches the frequently required HTTP requests made by clients which increases the speed of the Web page response from the client towards the server.

Security - Provides filtering of Internet access which is based on the source and the contents. Some proxy servers also provide with packet filtering and port blocking.

Management of IP address - Uses one IP address to connect to the Internet, hence does not require more public IP address for each host. Hence, it saves the use of public IP addresses.

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