[mitchs]

The big issue with v6 is you don't know what every ISP is doing with their IP space. The current RIPE recommendation is to delegate somewhere between a /48 to a /56 to every customer. Some ISPs might only delegate a 64, and perhaps typical home wifi setup may only use a single /64. For data aggregation maybe the error is ok, but I've wondered about what IP banning/filtering looks like for v6. Assume everyone gets a /64 and most cats will have 256 lives, and sometimes 16384. Assume everyone has anything larger than a 64, and you may block 255+ other people with the intended target.

[Gigachad]

IP based bans have long been obsolete imo. These days a combination of google captcha tracking and phone number verification is mostly used. A few things like IRC and 4chan still do IP bans which is painfully obvious when you notice you are randomly banned depending on what CG-NAT handed you at the time.

[toast0]

Start by banning /64's, but if you see a lot of nearby bans in some ASN, mark that one for bigger bans. Easy-peasy-ish.