I discovered yesterday evening that Lemmy.ml is blocking all inbound ActivityPub requests from /kbin instances. Specifically, a 403 'access denied' is returned when the user agent contains "kbinBot" anywhere in the string. This has been causing a cascade of failures with federation for many server owners, flooding the message queue with transport errors.
This doesn't appear to be a mistake; it has been done very deliberately, only on Lemmy.ml. Lemmy.world and other large instances do not exhibit the same behavior. It also isn't a side effect of the bug introduced in Lemmy 0.18. You can observe by sending the following in a terminal
> curl -I --user-agent "kbinBot v0.1" https://lemmy.world/u/test
HTTP/2 200
[...]
> curl -I --user-agent "kbinBot v0.1" https://lemmy.ml/u/test
HTTP/2 403
[...]
> curl -I --user-agent "notKbinBot v0.1" https://lemmy.ml/u/test
HTTP/2 403
[...]
> curl -I --user-agent "placeholder-user-agent" https://lemmy.ml/u/test
HTTP/2 200
[...]
Additional evidence of this not being a Lemmy 0.18 bug:
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This occurs when making web requests to any location on the Lemmy.ml webserver, not just ActivityPub endpoints.
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Go to https://fedidb.org/software/lemmy and pick an instance running 0.18.0. Perform the above commands, replacing the URL for Lemmy.ml with that particular instance's address.
If this continues, my instance may need to defederate from Lemmy.ml. This is especially problematic because Lemmy.ml continues to federate information outbound to other kbin instances while refusing to allow inbound communication from them.
Spoofing the user agent is less than ideal, and doesn't respect Lemmy.ml's potential wish to not be contacted by /kbin instances. I don't post this to create division between communities, but I do hope that I can draw awareness to what's going on here. Defederating /kbin instances entirely would even be better than arbitrarily denying access one-way. This said, we should all attempt to maintain a good-faith interpretation until otherwise indicated by the Lemmy developers. It's possibel that this is a firewall misconfiguration or some other webserver-related bug.
Relevant comment from me (#354 - [BUG] Critical errors/failed messages during messenger:consume)
Edits:
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Yes, people have already tried reaching out to the Lemmy instance admins in their Matrix room with no answer.
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Someone has posed a question on Lemmy.ml about the block here: https://lemmy.ml/post/1563840
If this is intentional, I have to wonder why they're doing it in such a troublesome way rather than defederating properly. If they want to defederate, so be it, but then just do that.
This approach only makes sense as a blanket defederation of all kbin servers. Seems shady.
Well, lemmy.ml is the lemmy devs. Kbin is a competitor to their software. They might hate that Kbin is growing really fast and I think is overall better than straight lemmy.
I think it's more likely they just disliked the fact most Kbin users don't support genocide, while Lemmy has a history of that. The Stalinist side of Lemmy, moderated and endorsed by the developers, has made fun of Kbin.social before
well we can't deny this fact.
It would be pretty against the spirit of ActivityPub if this were the case. Holding out to actually hear from them on this, hopefully, rather than assume such bad things about them.
They just recently had a software update I believe, so hopefully it's just a side effect of that.
Nah, probably just a configuration error on their end. Let's not jump to conclusions.
Lemmy devs aren't great people anyway, in terms of who you want to be developing software. Anyone that would think hardcoding word censorship into their software because it's theirs has a few screws loose, so I wouldn't put it past them to have done this intentionally.
Because "clever" authoritarians do the "isolating their people" kind of thing veeery quietly and not loudly.