A post on kbinMeta states that “Lemmy.ml is blocking all inbound ActivityPub requests from /kbin instances.” More details here, but the theory is that – rather than defederating – lemmy.ml returns a 403 ‘access denied’ message in response to any inbound requests from a user agent with “kbinBot” in the string. Upvotes, comments, and boosts don’t seem to be going through. However, it appears that lemmy.ml still federates information outbound to kbin instances.
I’m wondering if anyone here knows what is going on and why it might be happening? Federation between Lemmy instances and Kbin instances seems to be a selling point for both, so I’m sure others using both services are curious as to what’s going on.
Web developer here. This type of blocking based on user-agent would be easier done though the server configuration than in the Lemmy code anyway.
Returning “403 Forbidden” makes it seem like it’s not a bug or compatibility problem. The lemmy.ml server only appears to return 403 when the user-agent contains the exact string “kbinbot” (not case sensitive). That makes it seem deliberate.
I’m not saying it’s done with malicious intent, mind you. It could definitely be some kind of WAF or other automated blocking happening, maybe simply a misclick when blocking a flood of other bots, but that’s anyone’s guess until the admins respond.