A proxy server acts as a middleman that translates and evaluates request from clients to other network services. It is commonly used by network administrators to monitor the incoming traffics and contents to be served in the corporate network. In general, proxies can be classified into 2 groups, Forward Proxies and Reverse Proxies. Out of this two, Forward Proxies was the widely known proxies that have been sub-divided into few groups based on their implementation methods.
1. Forward Proxies
Forward proxies are usually working as a messenger between a private network and the public network, for example, Internet, to handle outbound requests. They are the common proxies that we use to isolate the private network from the public internet. They are often referred as mega proxies because they are able to manage a wide range of sources and high volumes of traffic. These proxies equipped with many features such as security, caching and web content filtering services, enabling network administrator to effectively manage and control the traffic flow through the proxies.
2. Reverse Proxies
Reverse Proxies are generally used to process requests from the Internet through a firewall to isolated and private networks. In short, they serve as front line soldiers, providing a layer of security which prevents the clients from directly accessing the backend network (e.g. the contents server). In addition, reserve proxies also often used as the load balancers and cache servers, to optimize server accessing speed.
3. Open Proxies
It was type of Forward Proxy. Open Proxies are available and accessible by online users in the form of a web browser or website. They are easy to use and popular among the internet community as users are able to conceal their actual IP address while surfing the web. In another word, they help to prevent the recipient domain from obtaining the user's actual IP address. Open proxies are usually offered by 3rd parties and free to use.
4. Web Proxies
It was type of Forward Proxy. Web proxies are also known as Anonymous Proxies. They hide the original IP address and prevent the remote domain server from obtaining the identity of the end users. In addition, they also work like a cache server. They save a copy of the files or websites in cache and return the data to users on next visit instead of re-downloading the entire contents. They therefore shorten the content delivery time and reduce unnecessary bandwidth utilization. This type of proxy servers are typically difficult to trace as they allow users to spoof their IP address for web surfing.
5. Transparent proxies
Transparent proxies are a variant of Forward Proxies. As the name indicated, they do not intercept and modify the requests or responses passing through the proxy servers, nor enforce any local policy towards the traffics. Transparent proxies usually sit between the client and internet acting like a gateway. However, they do not require special configuration on clients' browsers, hence, in many cases clients may not aware of their presence.