The proxy server is a computer device that is interposed between the corporate network and the Internet. Three roles are vested: caching, movement recording information and filtering. It sometimes also refers to the security of the computer system of the company, the role to be assigned to another device called a firewall. The author’s opinion is that, for the company, the proxy server is a real nuisance, while the firewall is a device highly recommended.
The proxy server is a pathetic censor
The proxy server software usually allows a list of words which must be absent from the information included in the company. Officially, we talk about eliminating violence, racism … but in practice; it is the language of sex that is always in question. In the examples which we are aware, installing a proxy server has always found its source in the prudishness of an entrepreneur, outraged that some staff visit adult sites using workstations computer at home.
But if the proxy server is a good spy, this is against a poor censor. The proxy converts the string into a sequence of binary digits, then search if this sequence is present in the information that passes through it. There is no distinction between a text file, an executable, a pilot, or an image. As the terms of the vocabulary of sex are generally quite short, the probability that the sequence of binary digits can be found in any file is far from negligible (5% in the example mentioned below). Daily proxies reject pell-mell useful files and texts licentious. In practice, if you really want to use as a filter proxy entrusting a long list of forbidden words, it simply prevents the company personnel to use the Internet properly.
The role of proxy server filter
The proxy server is a censor totally devoid of intelligence. Using the same string, it may as well stop a printer driver that page for adults.
The firewall as the proxy, the firewall is a computer interposed between the local network and the Internet business, but it has very different software. In its latest version, the software firewall functions to refuse entry to any information that is not a response to a question after the company, the safety rate is then very high.
Attention! Some documents and even some “experts” are happily confusion between proxy server and firewall. It makes a mockery of the world, because daily proxies operate at the highest level of the OSI model (layer “application”), while the firewall operates at 3 (“network” layer). It is true that some publishers sell both bundled software in the same “package”, which can be confusing – especially as computer dealers who know their products are rare. When you want to use them together, proxy and firewall can be installed on the same machine or on two separate machines.