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

It's a fact, that the best application defence is its code and security, not a firewall blocklist. If it's an essential matter for you to have real true users - you have to use two-factor authentication. Blocklists are totally useless nowadays.