Cloaking

Also known as: IP delivery

Cloaking is a form of search engine optimization in which a different version of a Web site is served to search engine spiders than regular visitors see.

By showing different content and links, an advantage could be obtained making the site appear higher in Google. However, the technique is a form of manipulation(black hat SEO) that can be penalized with a penalty.

In order to apply cloaking, spiders and visitors on the server side need to be distinguishable from each other. This can be done, for example, on the basis of user-agent or ip-address. Spiders usually make themselves known in the http-headers and also the ip-ranges of, for example, Googlebot are commonly known. A server-side script then causes search engines to see a different page than the visitor. This version may contain, for example, texts with additional keywords.

Distinction between unlawful and lawful cloaking

There are also legitimate purposes that can strictly be considered forms of cloaking. Such as serving a website in different languages based on its ip address (IP delivery), or showing different ads based on location(geotargeting). Similar recognition factors can be used to show the same content but from a different server, as in a content delivery network.

Distinctions between unlawful and permissible use of such techniques can be made by, among other things, whether there is a question of obtaining advantage by distinguishing a particular group (for example, search engines). Also relevant is whether being able to see the deviant content is only a choice of the server, or whether it can also be obtained by other means.

For offering a Web site in different versions, it is recommended to look at the "accept language" sent along by browsers in the headers, and preferably give the separate versions of a site in different languages their own URLs.