Πέμπτη, 5 Απριλίου 2012

Proxy servers for dummies

Many people using computers probably heard about proxies, but they have no idea what a proxy server is. Here is short introduction into the world of proxy servers, or proxy servers for dummies. Maybe it will come handy some day to know what a proxy server is.

What are proxies?

Proxy servers of proxies are actually computers or applications that act as intermediaries between your computer and the internet or other networks you are connected in. For example, when you connect to a proxy server and request some connection, contents, file or other, the proxy server first checks whether it has what you need (it searches its cache). If it does, it sends to you immediately, thus saving time. If the proxy server does not have what you are looking for, then it forwards your request to other servers and returns the information for you. So, when the next time you will request the same contents, connection or file, the proxy server will provide it immediately since it keeps it in its cache. In this manner, proxy servers can save time and provide more efficient and more reliable connection. Sometimes, proxies can make change of your request or change the information it returns back to you due to safety or other settings. Proxies are often used to filter the contents that can be available to users. For example, schools, high schools, universities or companies can adjust proxy servers to filtrate the contents that users search and get in order to protect the system from malwares and malicious programs, as well as to prevent users from getting prohibited contents, such as pornographic sites, adult contents or pedophilic contents and other contents not appropriate for users under certain age.

Web proxies

We hope that now it is much clearer now what proxies are. Now, let us see the types of proxy servers. Depending on their application, there are few types of proxies or proxy servers. The first and the most often used type are the web proxy servers. Web proxies connect multiple users to the internet. Their role is to accept and process the requests from users and provide responses. If they have the information or the contents users ask, the web proxy server take them from its cache and sends them to the user. If not, it connects to other remote servers and provides response to the request. The requested information stays in its cache, so the next time you ask for the same information, connection or contents; it will send it to you immediately. Web proxy servers use algorithms to process the requests they receive and keep. For example, your proxy server can scan the contents it has in its cache and on the basis of the Least Recently Used of Least Frequently Used algorithms to delete the contents that you least use or the contents that you use least frequently.

What other types of proxies are there?

Besides the web proxy server, there are other types of proxy servers or proxies. Transparent proxy servers identify their IP address and make it available for the other servers to see. This is unconvincing from the point of view if you want to remain anonymous while browsing or accessing to sites, but is pretty convenient in cases when hidden IP addresses would prevent you from getting the information and the contents you are looking for.

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