harman03
:)
Everyone one of you, who is reading this article might have known or used what are called as “proxies” either for anonymous browsing or for requesting some content that your server room filters and doesn’t allow. Most of us in colleges face this problem of “request denied” by the server room for a webpage or site which has been blacklisted for having adult or entertaining content!!! Here proxies come to our rescue.
But what is a proxy server and how does it functions?
A proxy server is a computer system or a system running an application within a network that acts as an intermediate between a client that requests from a server with the resources. A client connects to proxy server requesting for some specific service like a connection or a web page from a different server. The proxy server first filters the request by ip address or any of it’s defined protocol and when after the request successfully passes the filter test, it is evaluated and the proxy connects to the relevant server and demands the service on behalf of the client. Theproxy server may also pick up data from it’s “cache” that has been previously requested by the same or different clients. This quickens up the process significantly.
Proxy servers are useful in many ways :
- To keep the clients anonymous for security purposes.
- To speed up the client-server request process through caching.
- To provide content filtering, example to blacklist adult websites.
- To scan outgoing content for viruses or malware or to prevent data leak protection.
1. Gateway Proxy - A proxy server that passes requests and replies unmodified is usually called a gateway or sometimes tunneling proxy.
2. Reverse Proxy – A reverse proxy is (usually) an Internet-facing proxy used as a front-end to control and protect access to a server on a privatenetwork, commonly also performing tasks such as load-balancing, authentication, decryption or caching.
3. Hostile Proxy – Since proxy servers act as a bridge between the client and the main server, proxy operator can actually look at all the requests sent by the client. Thus passwords must be sent over a cryptographically secure connection like SSL.
4. Open Proxy – Anonymous open proxies allow users to conceal their IP address thus making web browsing anonymous.
5. Content-Filtering Proxy – These servers are employed in every organization to filter, block or allow content between client and server depending upon the acceptable use policy. Some common methods of filtering are URL or DNS blacklists, URL reg-ex filtering, MIME filtering or keyword filtering.
