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:

  • This occurs when making web requests to any location on the Lemmy.ml webserver, not just ActivityPub endpoints.

  • 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:

  • Yes, people have already tried reaching out to the Lemmy instance admins in their Matrix room with no answer.

  • Someone has posed a question on Lemmy.ml about the block here: https://lemmy.ml/post/1563840

  • Eisenhowever@kbin.social
    0·
    1 year ago

    Doesnt surprise me, the developers of lemmy (which are owners of .ml) have an agenda. They are into censoring on ukraine news, and other stuff. I dont get why people are choosing lemmy over kbin when they are equally bad looking

    • UrbenLegend@kbin.social
      0·
      1 year ago

      Eh? What are you talking about? There’s literally a bunch of Russia and Ukraine news at https://lemmy.ml/c/worldnews. This rumor mill needs to stop. People started some bad rumors about Lemmy devs just because of their political association and now its blown up into full lies.

      I use both Lemmy and Kbin, but I prefer Lemmy for a bunch of different reasons:

      1. Interface is cleaner and more performant.
      2. Getting to your list of subscribed magazines in kbin is a pain in the ass. Why is it buried in Settings?
      3. Kbin votes are public. This is just bad for privacy. It’s one thing to say that votes are public due to federation, and whole other thing to blatantly show it in the UI. There’s a reason why voting at a government level is kept secret, just sayin’.
      4. Also why the hell are they called magazines? None of the names in kbin map to existing conventions. “Threads” are posts. “Magazines” are communities or groups. I never get used to it because it isn’t natural to call these things the way kbin calls them.
      • Bodleum@kbin.social
        1·
        1 year ago

        I think liking an internet post and voting for the leadership of the government are not suitable for comparison here.