How a proxy sever works while browsing internet?

Browsing the internet from a home PC, there are several elements that make the whole process possible.First of all, on one end, we have our home PC. This PC is connected via its modem to the ISP’s server, which in turn is interconnected to servers around the world that host the specific web sites that we are requesting.

From a web browser, we send a request to access a specific website by typing the site’s address, for example, www.findproxy.org.

When we hit “Enter”, this request is sent to our ISP’s server, which identifies the request. If the ISP has a proxy server with cached requests, when retrieving our request it will look up the information in its cache to determine if the proxy can comply or not. This means that the proxy server saves all requests made from users to its cache, so that the next time another user makes the same request, it does not have to retrieve that same information from the original server. The proxy server responds by sending the information to our PC from its cache.

On the other hand, if the proxy server cannot comply, it will send the request to the real server that hosts the specific website that we are requesting. The host server sends that information to the proxy server, which can then cache the response for future requests, and then sends the information to our PC. Sometimes, more than one proxy server can be involved, as some sites, like MSN, Yahoo, and AOL have several proxy servers that respond to requests from their cache, thus reducing the amount of petitions to the main server and reducing response times.

In a corporate network, even more elements form part of the process. Apart from the possibility of having its own proxy server to improve performance, the proxy can also act as a filter from the employees’ terminal, blocking attempts to access specific content from their web browsers. Additionally, companies have mail servers that store and distribute emails over its local network and WAN. All potential viruses are filtered at this stage before it can reach an employee’s PC. Servers also provide additional security through firewalls either from the proxy itself or from a firewall server dedicated to such purpose.