>>11443
He uses Tor.
Tor doesn't get IP hashes.
Best practice to treat annoying posters: ignoring them, they will get bored eventually.
If they spam or flood, turn on "Hourly thread limit" in the board settings, or enable captcha temporarily.
If they spams through a thread, let him do it for a while, then mark the checkboxes at his posts, and click delete at the bottom of the page. You can delete quicker and with less effort, than he can post.
Most importantly: have patience.