Submitted 9 months ago by NotSpez@lemm.ee to [deleted]
Ok so imagine I’m on instance A, which is federated with instance B but defederated with instance C. Can people from instance C see a post I make on instance B and vice-versa?
Defederation means that you can’t see the instances you defederated from, but they can see all your posts regardless of where they are.
Yes. Though I’m not sure if they can see comments you make.
So:
A blocks C
C does not block A
B does not block any
Each instance has a local version, but there is a “True” version, which is located at the instance where the community is hosted. The “True” version gets sent to everyone else
User from instance A post in a community hosted in instance B. First the packet gets processed at instance A, instance A updates it’s local version of the community, the local version than gets sent to the instance where the community is hosted. Instance B received this information. Instance B updates it’s “True” version. Then the “True” version is sent to everyone else. Instance C receives this, and updates its local version. They’ll see any post/comments from instance A.
But if your reverse this, everything would be same except the last part. When Instance A receives any update, the instance first checks where each post/comment comes from. If a post/comment is from an instance in the block list, it is discarded. Therefore, users in instance A do not see those content from instance C. That’s what defederation is, a filter in their end.
Instance A will reject any direct connections to instance C, both inbound and outbound. And instance A also scan any incoming updates from any other instances, and discard any post/comments in the block list. But there is no way for instance A to send content to instance B while not letting instance C see it. Instance B decides who they’ll send it to.
Wow, great explanation. Thank you so much!
Illecors@lemmy.cafe 9 months ago
Probably. That will depend on whether instance B is federated to instance C. The home instance of a post is what defines federation policy.