A proxy is a server that connects users to other servers. In other words, it's a sort of server middle-man. When you access a website for example, your server requests information from that website's server. By using a proxy though, you're asking another server to make that request and then transfer the information to your server so you can access it. Originally, the proxy server was invented as a way to simplify and control the complexity of distributed systems. Today though, most proxies are web proxies, facilitating access to content on the World Wide Web and often filtering it depending on your server's protocol.
Uses of Proxies
While in most situations you would want to eliminate the middle-man to make things more efficient in terms of time and cost, when it comes to the internet, the proxy middle man can be quite useful. A proxy server is used for many different reasons. At your place of work for example, a proxy server is used to block websites your boss may not want you accessing while on the job, to keep track of the sites you do visit, or to scan your outgoing content for sensitive company information in order prevent data loss. Another common use is for security purposes. A proxy server can scan incoming content for malware to prevent your network from getting a virus or being hacked. Of course, proxies can be used to get around these features as well. Some proxies are designed to give you access to prohibited sites, to get around internet filtering, and to keep your internet browsing identity anonymous.
Types of Proxies
Because of their many different uses, there are a large variety of proxy types. A basic proxy that simply passes content back and forth is called a gateway or tunneling proxy. Think of it as your door to the internet. A reverse proxy prevents unwanted access coming from the internet to your private network. This is great for security purposes. Forward proxies, on the other hand, control outgoing connections, allowing you to access most internet locations. Most proxies can be categorized as a type of forward proxy. An open proxy, as its name suggests, is a server that is accessible to all internet users. Gordon Lyon, famous network security expert and hacker, estimates there to be "hundreds of thousands" of open proxies on the internet. One type of open proxy is called an anonymous open proxy, which allows people to hide their IP address while browsing the web. There are also PEPs, or performance enhancing proxies, that are intended to improve TCP performance. In short, they help you load and transmit content more efficiently.
Whether you realize it or not, you are probably accessing this document through some type of proxy, most likely an open tunneling proxy. If you want a more specific proxy either for security or anonymity purposes though, you can buy a proxy from any number of proxy server providers like www.proxy51.com. In general though, it's always a good idea to know what the proxy you're using does and what a potential proxy server you'd like to buy will be able to do.
Whether you realize it or not, you are probably accessing internet through some type of proxy, and it's a good idea to know what your proxy does and what other proxy options are available.
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