Spambots
Spambots surf the web, looking for contact us, registration, guest book, blog comment, forum, newsletter sign-up and any other web forms to submit spam links to. Some spam messages are targeted towards readers promoting whatever the spammer is trying to sell. Other spam messages are simply hyperlinks intended to boost search engine ranking for the spammer's site. If you have a web site with forms that are accessible from the public web, you need to take security precautions to protect against spambots, before publishing them. The type of security precautions that you can take are:
- Email confirmation: The easiest way to confirm whether a genuine user registered or signed-up for your newsletter is to send a confirmation email to the address provided by the user. Ask them to log in to their email and click on the confirmation link. Spambots provide made-up email addresses and so will not be able to overcome this test.
- CAPTCHA: Ask the user to complete a simple test using distorted letters and numbers. These are created to make it difficult for spambots to decipher. Carnegie Mellon University provides a free service called reCAPTCHA (acquired by Google a few months ago). You can register and use this service with minimal code on your web site.
- Commercial Services: There are also several commercial services available to prevent spambots.
