Tag Archives: spam

Ways to filter bots


  1. Most popular is recaptcha by google
  2. Honeypot technique – include a hidden field, if it is filled, then it is a robot
  3. A simple random questions. E.g. is fire hot or cold , five – 3 is ___
  4. http://nomorecaptchas.com/ (with price)
  5. https://visualcaptcha.net/ (no longer developed but they claim it still work)
  6. Algorithm
    1. after 5 failed attempt, lockout IP for 15 minutes
    2. if 5 times lockout, lockout IP for 24 hours
    3. if 3 times lockout, blacklist IP permanently (option for sys admin to clear)
  7. More alternatives