Experimental DoS mitigation is in tor master https://lists.torproject.org/pipermail/tor-relays/2018-January/014357.html Full thread above, some potential affected usage below... https://lists.torproject.org/pipermail/tor-relays/2018-February/014393.html https://lists.torproject.org/pipermail/tor-relays/2018-February/014396.html