What is a proxy server and how to use it?

Proxy server - service (set of programs) in computer networks, allowing customers to indirect requests to other network services. First, the client connects to the proxy server and requests a resource (for example, e-mail), located on another server. Then, the proxy server either connects to the specified server and obtains the resource from it, or returns the resource from its own cache (in case if the proxy has a cache). In some cases, the client's request or response may be modified by the proxy server for specific purposes. As a proxy server can protect a client computer from some network attacks and helps keep client's anonymity.

Most often, proxy servers are used for the following purposes: Providing access to computers on the local network to the Internet. Data caching: If frequent access to the same external resources, it is possible to keep a copy on the proxy server and produce on demand, thus reducing the load on the channel to the external network and accelerating client receives the requested information. Data compression: a proxy server to download information from the Internet and transmits the information to the end user in a compressed form. These proxy servers are used primarily to save the external network traffic or internal client - a company in which a proxy server. Protects the local network from outside access, for example, you can configure a proxy server so that local computers will access external resources only through him, and the external computers can not access local general (they "see" the proxy server). See also NAT. Restricting access from the LAN to the outside, for example, you can block access to certain websites, restrict the use of some local Internet users, set quotas on traffic or bandwidth, filter ads and viruses. Anonymization access to various resources. A proxy server can hide the source from a query or user. In this case, the target server can see only information about the proxy server, for example, IP-address, but has no way to determine the true source of the request. There are also distorting the proxy server to which the target server false information about the true user. Bypass restrictions. Proxy servers are popular among users of countries where access to certain resources is limited by law and filtered. A proxy server that can be accessed by any user of the Internet, called open.