Forward & Reverse Proxies PDF

106 (Forward & Reverse) Proxies What is a proxy server? (aka Forward proxy) A proxy server is an intermediate piece of software or hardware that sits between the client and the *...

106 (Forward & Reverse) Proxies What is a proxy server? (aka Forward proxy) A proxy server is an intermediate piece of software or hardware that sits between the client and the * * * * * * * server. * Clients connect to a proxy to make a request for a service like a web page, file, or connection * * from the server. * Essentially, a proxy server (aka the forward proxy) is a piece of software or hardware that * * * **~ ~** * facilitates the request for resources from other servers on behalf of clients, thus anonymizing the * * * * * * * client from the server. * A forward proxy: * * Typically, forward proxies are *used to * *** cache data*, *** *** filter requests, *** *** log requests, *** * or transform requests (by adding/removing headers, encrypting/decrypting, or compressing a * *** *** * * * * * * * * resource). * A forward proxy can hide the identity of the client from the server by sending requests on ** ** **~ ~** behalf of the client. * * In addition to coordinating requests from multiple servers, proxies can also optimize request traffic * * * * * * from a system-wide perspective. * Proxies can combine the same data access requests into one request and then return the result * ** *** * * * * to the user; this technique is called collapsed forwarding. **~* *~** Consider a request for the same data across several nodes, but the data is not in cache. By * * * * * * * * *  routing these requests through the proxy, they can be consolidated into one so that we will only * *** ** * read data from the disk once. Reverse Proxy A reverse proxy retrieves resources from one or more servers on behalf of a client. These resources * * * * * are then returned to the client, appearing as if they originated from the proxy server itself, thus * * anonymizing the server. Contrary to the forward proxy, which hides the client's identity, a reverse * * * *** proxy hides the server's identity. ~ ~*** * A reverse proxy: * In the above diagram, the reverse proxy hides the final server that served the request from the client. * * The client makes a request for some content from facebook.com; this request is served by facebook’s * reverse proxy server, which gets the response from one of the backend servers and returns it to the * * * client. A reverse proxy, just like a forward proxy, can be used for * * * * *** caching, *** *** load balancing, *** * or routing requests to the appropriate servers. * *** *** Summary A proxy is a piece of software or hardware that sits between a client and a server to facilitate traffic. ** ** *** *** A forward proxy hides the identity of the client, whereas a reverse proxy conceals the identity of the ** ** * * ** ** * server. * * So, when you want to protect your clients on your internal network, you should put them behind * a forward proxy; * * * on the other hand, when you want to protect your servers, you should put them behind a reverse * * * * proxy. *