What is a proxy?
A proxy, it is an agent, an intermediate.
On the Internet, there are different types of proxy. The most common are HTTP proxies. They support both HTTP and FTP.
An HTTP proxy is a program that acts as an intermediary between an HTTP client and an HTTP server: it receives client requests and forwards them to the server, and is the same for the server response. Thus, a proxy is both a client and an HTTP server.
Proxies are commonly used when the network is protected by a firewall, or to serve as cache.
When a customer uses a HTTP proxy, it sends all requests to this proxy instead of send directly to the server. A request sent to different proxies in the request line contains the full URL of the resource instead of the path on the server.
In this way, the proxy knows which server forwarding the request, although nothing prevents the proxy makes use of another proxy for the resource.
What’s the point?
The proxy can protect you
It can allow you to log out and ban computers connect internet to come on your own. This protection function is often included in proxy firewalls (fire walls), computers programmed to filter communications between networks (for example between the corporate network and the Internet).
The proxy can hide information about your computer
In fact, when you surf all websites can know what site you came from, what browser you are using, what is your operating system, your IP address … Some proxies hide this information. These are called anonymous proxies.
The proxy can store the most requested pages
So if you ask several times http://www.site.com/index.html page, the proxy will immediately search without going to www.site.com. If you are close to the proxy, it can speed things up. He then called proxy-cache.
Since you ask all your pages to the proxy, it can know all the sites you have visited.
Some Web sites require passwords. As you go through the proxy, the proxy will know your passwords (unless you use HTTPS / SSL).
The proxy provides the pages, but it is also possible that the proxy changes on the fly before you give them to (this is rare, but possible).
Some proxy can be configured to censor sites.
Therefore you have to trust the proxy administrator. You decide whether you want to trust the proxy server of your ISP. For those companies … this is a must see! Experts estimate that 70% of U.S. companies consider employee access to the proxy.
Nevertheless, I recommend that you disable – if you can – the proxy when you need to access sites that require passwords.