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
[...]

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.

Relevant comment from me (#354 - [BUG] Critical errors/failed messages during messenger:consume)

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

    • Deceptichum@kbin.social
      0·
      1 year ago

      Before assuming no one has asked them, let’s read the post

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

      • ripcord@kbin.social
        1·
        1 year ago

        Ok, but, as the thread over there says, it’s not like they’re singling out kbin as far as the code shows. Just because no one there has answered yet doesn’t mean they’ve refused to answer. Give it some time or some actual replies before assuming the worst.

        Also that edit was added after my question.

        It’s been a few hours, this is way way too fast for the pitchforks to come out.