How not to suffer a sandbox penalty?
Sandbox is a type of penalty imposed by Google. This sandboxing seems to apply when abnormal behaviour is observed with regard to the acquisition of backlinks.
The most affected websites are mostly the youngest ones, during their first year of aging. Actually, there are priority targets regarding "negative SEO" actions.
As a consequence, it is therefore advisable to slowly start a netlinking campaign for a new domain name and to focus on a certain quality of links.
However, there is no automatic penalty (or filter). Indeed, a new website can easily and quickly obtain an unbelievable number of links and get away with this.
It is a typical "buzz" effect and that is how search engines identify it. A penalty would therefore be completely illegitimate and counterproductive for the relevance of search engines.
Apparently, there are many types of sandbox than can affect all or part of a website, or even some keyphrases.