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
Go to the relevant domain’s front page (e.g https://kbin.social/d/kbin.social for kbin.social).
The URL scheme is “https://kbin.social/d/DOMAINHERE” assuming you are currently on kbin.social.
On the right in the sidebar you can see “Domain” and below that options to subscribe or to block.
Really it’s the same thing as magazines, just that you generally don’t visit the domain itself.
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kbin is still in its growing pains phase. there are tons of little user experience items that need to be worked on. good thing is that @ernest is working hard on it.
Yeah no shade intended, just more reason to explain it to people. Ernest is a G.
Now I’m curious what would happen if I defederated from Kbin.social on kbin.social
Guess you’ll simply no longer see posts from kbin.social
Could you see anything…? All kbin.social items being blocked, not just the content?
I’m genuinely not sure, but since ernest shows up as mod on all external magazines, I wouldn’t be surprised if it blocked everything.
In fact, If you go to https://kbin.social/d/kbin.social today, you do see the external posts.
Blocking isn’t defederating. The instance controls federation, but blocking is on a user basis.
Does that actually work for you? I’m still seeing posts from magazines on domains that I blocked that way. It looks to me like it only blocks articles, and also link posts to the domain, but not link posts on magazines from the domain.
What I hear is that a copy is still made so the posts made before defederalization is available and basically forks without them connected now at the point of being deferated
It was all in my face for all this time!!!