Lemmy has been using whitelist based federation right up until people started moving over from Reddit, so it’s not exactly a new approach.

With new domains costing anywhere between $3 and nothing at all, setting up thousands of spam servers isn’t that difficult or expensive. There’s already a tool that’s designed to allow bypassing blocks automatically by simply feeding it a second domain. If spammers actually cared about the Fediverse, they’d be all over it in no time.

But the big danger right now is that free, open servers, big or small, don’t have much in the way of verification or hot prevention. Some instances don’t have any protection at all (which the Japanese spam wave abused), others are using basic CAPTCHAs that copilot will happily solve for you. On centralised services this problem can be fixed temporarily by using technologies like strict device attestation (rip Linux/custom ROM/super cheap phone users), but in a decentralised environment this won’t work. Then there are the many, many servers that never received patches, and still have the Mastodon account takeover vulnerability, for instance.

Small servers will have to prove themselves to the servers they want to federate with, or abuse will be too easy.

I don’t think temporary blocks are a solution. Right now, the attacks focused on tiny servers with one or a couple of users, but with the rise of AI I don’t think the bigger servers will be able to stop dedicated spammers. Right now the spam wave is over, mostly because a few of the Japanese kids got arrested/had their parents find out. Right up until the very end, Lemmy and Mastodon were full of spam.

I don’t want this recentralisation to happen, but I think the Fediverse will end up like email: strict, often arbitrary spam prevention systems that make running your own very difficult. After all, email is the original federated digital network, and it’s absolutely full of stupid restrictions and spam. ActivityPub may have signatures to authenticate users, something that even DKIM still lacks, but the “short message + picture” nature of most Fediverse content make it very difficult to write good spam detection rules for. Maybe someone will create some kind of AI solution, who knows, but I expect deliverability to become as problematic as with email, or maybe even worse.

I can’t think of a good solution here. Our best bet may he hoping that people won’t be too dickish, or to keep the Fediverse out of the mainstream so all the spammers go to Threads and Bluesky first.