Yes, instance bans propagate out to the federation. But if user@a.com gets banned, they can just go sign up as user@b.com.
this post was submitted on 17 Jun 2023
2 points (100.0% liked)
Lemmy
12548 readers
25 users here now
Everything about Lemmy; bugs, gripes, praises, and advocacy.
For discussion about the lemmy.ml instance, go to !meta@lemmy.ml.
founded 4 years ago
MODERATORS
Thank you, it appears to be this way.
Same question.
My theory is:
When the instance admins ban one of the users off of their instance, the ban event gets transmitted to everyone that’s federated, so that other instances can stop seeing posts from that user too.
That would imply that any instance admin, even those that created theirs for themself only, can just ban users on other instance. That would be a major attack vector and it kind of defeats the purpose of the autonomy each instance is supposed to have...
Are those instances you federate with?
Yes, they all only from instances i federate with.
When you say "my own instance" do you mean an instance you set up yourself and are the administrator? If so how and where did you set it up?
Yes. I have a VPS and I am using their Docker files: https://join-lemmy.org/docs/en/administration/install_docker.html
There should be a public modlog which should tell you when and why someone was banned. I haven't set up my lemmy instance yet, did you maybe leave your instance unprotected for long enough so some could add bans? Or did you use an old database with data from a previous instance? Did you pull the wrong docker image?
Everything is running fine. It is as @jon@jon@lemmy.tf and @neoney@lemmy.neoney.dev write.
If I am server A, and I federate with B. If user@B is banned by B, this is propagated to me, so that A does not see content from B that comes from user@B. It makes sense.
What I don't understand is why does server B have to tell server A that user@B is banned on B, instead of just not letting user@B login anymore and thus disallowing the creation of further content by user@B?
And maybe A wants the content by user@B, so why can server B dictate bans that server A has to enforce?
What happens if server A ignores them?
As an instance would I be able to flood another instance's ban list by just pretending to have trillions of users that are all banned?
Given that I asked the question in the first place, here is how I make sense of it after some answers and looking at the modlog.
What I don’t understand is why does server B have to tell server A that user@B is banned on B, instead of just not letting user@B login anymore and thus disallowing the creation of further content by user@B?
Because A sees B's content, but on A server. user@B is banned on B, hence, A keeps seeing B content, but not user@B content on B. user@B can still register on A and post there.
And maybe A wants the content by user@B, so why can server B dictate bans that server A has to enforce?
Because user@B's content, while copied and displayed on A, is still B's content. B bans the user and their content everywhere. Again, user@B can register elsewhere and start posting.
What happens if server A ignores them?
From what I can see, if I am A, I cannot unban user@B in any way. user@B can register in my instance, though. I can ban user@A afterwards (or not).
As an instance would I be able to flood another instance’s ban list by just pretending to have trillions of users that are all banned?
I think so. I federate with Beehaw. If Beehaw bans everyone, my banned user list will get quite long.