OPEN PROXY SERVERS

In computer networks, a proxy server is a server computer system that acts as an intermediary for requests from client computer systems seeking resources from other servers. A client connects to the proxy server, requesting some service available from a different server. The proxy server evaluates the request according to its filtering rules. A proxy server can be placed in the user's local computer or at various points between the user and the destination servers on the Internet.
An open proxy is a proxy server that is accessible by any Internet user. With an open proxy, however, any user on the Internet is able to use this forwarding service.
An open proxy allows a user to conceal his IP address and thereby help preserve his anonymity and maintain his security while browsing the Web or using other Internet services.
It is possible for a computer to run as an open proxy server without the computer's owner knowing this. This can result from misconfiguration of proxy software running on the computer, or from infection with malware (viruses, trojans or worms) designed for this purpose.. If it is caused by malware, the infected computer is known as a zombie computer.
There are hundreds of thousands of open proxies online. Running an open proxy is a high risk for the server operator; providing an anonymous proxy server can cause real legal troubles to the owner. Such services are frequently used to break into foreign computer systems, child pornography is usually consumed through proxies, and illegal content is likely to be spread through such proxies. Because open proxies are often implicated in abuse, a number of methods have been developed to detect them and to refuse service to them.