Is it possible to block Tor users?

Question

Would it be possible to block Tor users? (https://www.torproject.org/)

Due to the nature of the site I run I should do all I can to stop multiple accounts and block cert

Answer 1

Tor is much easier to block than other open proxies since the list of exit IP addresses is known and published. Read the answer at https://www.torproject.org/docs/faq-abuse.html.en#Bans and if you still want to block users from accessing your site you could use https://www.torproject.org/projects/tordnsel.html.en or the Bulk Exit List exporting tool.

If you use the Bulk Exit List exporting tool be sure to get a fresh list often and expire the old blocks since the list of IP addresses change.