A free, distributed, open-source project to help website administrators track, stop, and prosecute spam harvesters stealing email addresses from their sites.
www.projecthoneypot.org
the key would go in this section:
Pot
Check DNSBL on registrationCheck IP addresses in DNS block lists when a new user registers to help prevent spam. If the StopForumSpam integration is not enabled, the Tornevall DNSBL will be checked.
Project Honey Pot key:
I’d also recommend setting the registration timer to 10 or 15 seconds.