Knowledgebase: General
SPAM-FREE website forms and guestbook
Posted by Dan Moses on 08 December 2006 01:16 AM
Captcha Codes defeat Robots

Spam bots can crawl the web looking for forms with no defense. Once found, the form is auto-filled and submitted. The idea is that the message the spam bot carries is submitted to you the reader AND should your form issue an auto-reply, your email address will be captured and enslaved for further exploitation.

The best defense you have against these spam bots is a Captcha Code. This challenges all visitors, to enter a randomly generated sequence of characters into your form which is then tested to determine whether or not the submitter is a human that can read. The Captcha code appears as an image on your form, sometimes partially obscured by noise, but always sufficiently legible for a human to correctly read. If the code is correctly entered, the form is successfully submitted.

This is a simple and effective method for stopping spam. Any form is susceptible to spam bots, and spam bots can be relentless, often returning to attack the same forms hundreds of times a week which cannot only occupy your time, but drain your server's resources to the point where legitimate visitors cannot utilize your forms.

Search the search engines to find some scripts using this technology to prevent your account from being hijacked by spammers.
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