Challenge-response spam filtering

Redirect to:

• Challenge–response spam filtering

• From a modification: This is a redirect from a modification of the target's title or a closely related title. For example, the words may be rearranged.
  • Please note that there are many more specific templates. Please use {{R from alternative spelling}}, {{R from alternative hyphenation}}, {{R from alternative punctuation}}, {{R from alternative spacing}} and {{R from misquotation}} where relevant; see subcategories of Category:Redirects from modifications for other options (capitals, abbreviations, diacritics, plurals, stylizations, transliteration, ligatures, different parts of speech, etc.). If you are unsure which to use, this template is fine; someone will make it more specific later if necessary.
  • In cases of modification from distinctly longer or shorter names, please use {{R from long name}} or {{R from short name}}, respectively. An abbreviation should be tagged with {{R from initialism}} or, if it can be spoken like a word such as NASA and RADAR, use {{R from acronym}}.
  • Use this rcat instead of {{R from other capitalisation}} and {{R from plural}} in namespaces other than mainspace for those types of modification. This may also apply to several other subcategories of modification; please check those templates' output before saving if using outside of mainspace.