Ajax Control Toolkit NoBot

Modified on 2010/04/16 00:50 by Stephen Walther — Categorized as: Uncategorized

NoBot is a control that attempts to provide CAPTCHA-like bot/spam prevention without requiring any user interaction. This approach is easier to bypass than an implementation that requires actual human intervention, but NoBot has the benefit of being completely invisible. NoBot is probably most relevant for low-traffic sites where blog/comment spam is a problem and 100% effectiveness is not required.

NoBot employs a few different anti-bot techniques:


NoBot can be tested by violating any of the above techniques: posting back quickly, posting back many times, or disabling JavaScript in the browser.

NoBot Server Properties

The properties in italics are optional.

<ajaxToolkit:NoBot
  ID="NoBot2"
  runat="server"
  OnGenerateChallengeAndResponse="CustomChallengeResponse"
  ResponseMinimumDelaySeconds="2"
  CutoffWindowSeconds="60"
  CutoffMaximumInstances="5" />