WordPress.org

Author: Donncha O Caoimh

This plugin adds a stylesheet to your blog's html source code. When a browser loads that stylesheet a cookie is dropped. If that user then leaves a comment the cookie is checked. If it doesn't exist the comment is marked as spam.

For the adventurous, add these lines to your .htaccess and it will block spam attempts before they ever get to WordPress. Replace the Xs with the cookie that was set in your browser after viewing your blog. Make sure the lines go above the standard WordPress rules.

    RewriteCond %{HTTP_COOKIE} !^.*XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.*$
    RewriteRule ^wp-comments-post.php - [F,L]

If you use WordPress MU, replace wp-comments-post.php above with wp-signup.php to block spam signups.

    RewriteCond %{HTTP_COOKIE} !^.*XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.*$
    RewriteRule ^wp-signup.php - [F,L]