Ouch… I just had to realize that @matrix doesn't provide the ability to block other homeservers.
It's not possible because it messes up room states, great.
At the same time this will cause legal trouble for every server admin when illegal content is federated to your server due to a user of your server being in a channel it got shared.
Due to this it's a bad idea to recommend running a homeserver for more people than yourself. ☹️
@sheogorath You can simply add the domain of the server you want to block to your /etc/hosts with the IP 127.0.0.1 to block the connection.
@nipos Does this prevent content from coming in? And how does this prevent content that comes in with state events? As described in the issue, they are shared by other homeservers with your server?
@sheogorath It blocks only outgoing requests.I'm not a Matrix admin yet (planning to set up a server soon) and I know even less about the protocol but it was a idea how it could (at least partially) work.
@nipos Sadly, I think this is a protocol issues due to the nature of how rooms work. for now the solution seems to be removing all local users from channels where this content was pushed and remove this channel from the database.
This is will break a lot of channels :/
Reductingof media may be spread through servers and the media becomes unavailable too. Yet, the media is only downloaded go a home server if requested by a user. On small instances likely no to happen if room-admins deduct the content quickly. As an admin you of course always can delete the files from/download. I do occasionally and the content is downloaded again upon request and availability.
Let's make it a real world case: Someone sharing Nazi paroles in their Display name (means it's part of room state events) which is illegal in Germany.
As soon as your homeserver distributes that, you have a problem, as you are publishing illegal content. the only way to prevent this is to get rid of the entire channel at least for a while as otherwise the content will be loaded. And even at any point in future you may have legal trouble because one could receive those events.
@sheogorath @nipos Yes, may be a case but atm. it is the usage of the software and I barely think that people get issues with the government because of something they don't actively do but what is an outcome of the software usage. Same like Mastodon & Matrix an GDPR. You can't request a total deletion of your content/username. But that is service-inherent.
You can run instances for public without problems. But you have to be able to act as soon as you get informed/aware of illegal content and you have to make sure to get rid of it.
Right now, with synapse we are unable to enforce this and that will cause legal issues in a long term perspective.
I guess the current solution would be to disconnect users from channels that refuse to act on illegal content. But I'm still not sure how to prevent them from joining again.