A proxy server is defined as a computer offering a computer network service so that clients can create an indirect network connection with other network services. When a client is connected to a proxy server, he requests a connection or other available resource in a different server. The proxy server gives the resource, it can be given through connecting to a specified server or serving from a cache. There are also instances when the proxy server may alter the request of the client or the response of the server for different purposes.
One of the most common proxy applications is the caching Web proxy. It provides the closest cache of files and Web pages that are available on the remote Web servers; this will allow the clients of the local network to access the files and pages more reliable and quicker. When the proxy server receives a specific URL, the caching proxy then searches for the URL in the local cache. If it is found, the document will be returned immediately. Usually, the cache is using an expiry algorithm in order to remove the documents found in the cache and it is done according to size, age and access history. The simple cache algorithms are of two kinds, the Least Frequently Used (LFU) and Least Recently Used (LRU). The LFU removes the documents which are least frequently used while the LRU removes documents which are least recently used by the user.
In addition, Web proxies can filter the Web pages’ content served. There are some applications referred to as censor ware, they attempt to block the Web contents that are classified as offensive. These are implemented by the Web proxies while some web proxies reformat the web pages depending on the audience or specific purpose like reformatting web pages for PDAs and cell phones. Also, network operators have the capability to deploy proxies so that they can intercept the viruses threatening the computers as well as other hostile contents. You can read as well about Proxies alternative which are called “VPN Service such as hidemyass” and is a faster way to get anonymous online. You also can learn more about hidemyass vpn (hma pro) here. (in French).
The proxy servers have four different types, they are:
- Transparent Proxy – this proxy server is identifying itself as a proxy server and also makes the availability of original IP address via the http headers. The transparency proxy is only used for its capability to cache websites but it is not effective in providing anonymity for the users. However, using transparent proxy can help the user in simple IP bans. Also, it is transparent, meaning that the IP address will be exposed at the same time not transparent since the user will not know that he is using it.
- Anonymous Proxy – This proxy server is not making the availability of the original IP address. It can be detected but the good thing is that it gives most of its users’ reasonable anonymity compared to transparent proxy.
- Distorting Proxy – This proxy server makes an incorrect available IP address via the http readers.
- High Anonymity Proxy – This is the only type of proxy server that is not identifying it as the proxy server at the same time does not show the availability of an original IP address.
This is how the proxy server works and its four different types.