There's a little-known setting on Mastodon called "limited federation mode". In this mode, there is no federation except with instances that the admin has specifically named on an allowlist. This is a lot better for user safety, and may suit some instances.
- If you're on managed hosting, you can ask your hosting provider to switch it on.
- If you're maintaining Mastodon yourself manually, docs are at https://docs.joinmastodon.org/admin/config/#federation
More info at https://fedi.tips/creating-an-isolated-server
Creating an isolated Mastodon server | Fedi.Tips – An Unofficial Guide to Mastodon and the Fediverse
An unofficial guide to using Mastodon and the Fediversefedi.tips
