ban the entire /64. If banning the /64 is not enough, then ban the /48. If that is not enough, keep going up 4 bits until it is (most IPv6 allocations line up o

ban the entire /64. If banning the /64 is not enough, then ban the /48. If that is not enough, keep going up 4 bits until it is (most IPv6 allocations line up on a nibble boundary, hence the 4 bits)