Federation

[stribes]

Introduce optional federation support allowing Kestrel homeservers to interoperate while remaining independently operated.

Summary

Kestrel would support connecting seperate homeservers under a shared protocol, enabling cross-server messaging and account portability.

Goals

• Allow multiple independent Kestrel homeservers
• Enable users to communicate across servers
• Preserve per-server moderation and identity control

Scope

This proposal is focused on defining whether federation should exist and what constraints it must respect, not on final implementation details.

Notes

This is a long-term consideration intended for post-initial release planning and may evolve significantly as our system matures. It may also be abandoned.

[stribes]

I think one way to give each server its own full control over moderation and user policies is to implement some form of federation rules system, say if my homeservers minimum age is set to 16 then I can toggle smth for federation that will enable the rule to enforce that minimum age during federation aswell.

[DAHNEEV]

Such a system could easily be abused; if every independent server sets its own rules, it could configure those rules to mislead other servers (for example, regarding content restricted to a specific age group, assuming, of course, that servers are connected automatically in some way);
if we assume that servers in a federation must be connected, that is, both parties accept each other, then such rules don't make much sense, because the connection is manual, so the rules can be verified right away

[stribes]

Someone on the Rust Programming Language Discord suggested this:

Instead of trying to have federation enforce things like age requirements, homeservers could just have their own onboarding.

When a user adds a homeserver, it'd pop up with that homeserver's rules, If they accept, the server gets added. If they decline, it won't be added.

This seems a lot cleaner than the idea I had before where homeservers could define federation rules (for example, requiring accounts on other homeservers to meet a minimum age before being allowed to access this one). That'd also require disclosing your age to every homeserver your in, or some other kind of age verification data, which is probably best to be avoided.

It also means each homeserver is responsible for communicating and enforcing its own rules, instead of the federation protocol needing to understand them.

AGAIN, NOT MY IDEA

[DAHNEEV]

That's a much better idea, but it requires user confirmation. I would also add a mechanism that allows servers to be added without user intervention, such as a list of servers in the config file, or something like that. This would greatly simplify the subsequent scaling of a single server to, for example, different continents or simply additional server instances (in the case of high traffic).

[stribes]

PLEASE USE OUR DISCORD/MATRIX TO DISCUSS THIS IN THEIR SPECIFIED CHANNELS.