What is a Circumventor?

A circumventor is a method of defeating blocking policies implemented using proxy servers. Ironically, most circumventors are also proxy servers, of varying degrees of sophistication, which effectively implement "bypass policies".

A circumventor is a web-based page that takes a site that is blocked and "circumvents" it through to an unblocked web site, allowing the user to view blocked pages. A famous example is 'elgooG', which allowed users in China to use Google after it had been blocked there. elgooG differs from most circumventors in that it circumvents only one block.

The most common use is in schools where many blocking programs block by site rather than by code. Students are able to access blocked sites (games, chatrooms, messenger, offensive material, internet pornography, etc.) through a circumventor. As fast as the filtering software blocks circumventors, others spring up. It should be noted, however, that in some cases the filter may still intercept traffic to the circumventor, thus the person who manages the filter can still see the sites that are being visited.

Circumventors are also used by people who have been blocked from a web site.

Another use of a circumventor is to allow access to country-specific services, so that Internet users from other countries may also make use of them. An example is country-restricted reproduction of media and webcasting.

The use of circumventors is usually safe with the exception that circumventor sites run by an untrusted third party can be run with hidden intentions, such as collecting personal information, and as a result users are typically advised against running personal data such as credit card numbers or passwords through a circumventor.