This XenForo addon uses custom detection methods to identify automated and manual registrations that are trying to spam your forum.
You may score based on:
Visitor's country
E-Mail address
E-Mail length
Username
IP hostname
Internet Provider name
Open TCP port (requires PHP-sockets extension)
StopForum Spam API
Project Honeyport API
TOR client detection
Visit the addon's page: https://xenforo.com/community/resources/tpu-detect-and-block-spam-registrations.2973/