Disable external WordPress comment requests

You can disable external comment requests for WordPress. The following steps block requests to the wp-comments-post.php file that come from outside your WordPress site, which can help prevent comment SPAM.

  1. You should always backup your site before making any changes.
  2. Connect to your hosting with FTP
  3. Locate the .htaccess file
  4. Edit the file and add the following code:
    RewriteEngine On
    RewriteCond %{REQUEST_METHOD} POST
    RewriteCond %{REQUEST_URI} .wp-comments-post\.php*
    RewriteCond %{HTTP_REFERER} !.*yourdomain.com.* [OR]
    RewriteCond %{HTTP_USER_AGENT} ^$
    RewriteRule (.*) http://%{REMOTE_ADDR}/$ [R=301,L]
  5. Save and upload the updated file

Now it will be more difficult for comment SPAM bots to post on your WordPress pages and posts.

More info