We just enabled a narrow filter on all our customers' Mastodon instances that blocks those "Automated protocol deliverability probe" registrations from ever being created. If you host your own instance, here is the filter we use: https://gist.github.com/d--j/767afe195afd48a496eea87bc5f6b33d If you are a customer of ours and DO want to get these, please contact us and we will disable the filter for you. We still have the mail filter in place (see https://toot.io/@hosting/117286370646788376), but that only stops the confirmation emails from going out over our shared mail system. Those emails are apparently what the spammers are after. It doesn't prevent the registrations themselves. We currently do not prevent OAuth app registrations, and the "BoomProtocol" OAuth apps are still piling up. They don't do much harm, though. #bpSpam #MastoAdmin