Hi @angus, I can't be certain about what is actually happening, which needs an admin and knowledgeable person with the ActivityPub plugin, but I observe that this forum becomes slow or even unreachable at times and it looks to be related somehow to posts that are being federated. Notified about that in this post, saw it happening yesterday after @silverpill tooted this reply, and I got "503 Gateway timeout" from NGINX which I think may relate to this post.

I also noticed that SH becomes unresponsive when I publish a reply. This is because replies are delivered to many other servers, which start to load the reply tree, all at once. Sorry about that

if this is the case, then it is basically a "thundering herd" issue similar to how link previews can cause issues. to which the mitigation is that softwares should stop auto-fetching resources that might not ever be seen, and to instead use on-demand deferred "lazy loading" strategies.

Hey guys, I’ll have a closer look at this soon, hopefully tomorrow.

I disable my plugin for that trouble I’ve received many request no stop from the same souce-instance or many others instances making the same type of request without none delay limit, sorry but this is weird all time requesting and flooding my server is too much.

angus: Hey guys, I’ll have a closer look at this soon, hopefully tomorrow. I don’t want to put pressure, and it may be inconvenient time now in the Summer vacation period, but if you have an opportunity to delve into the issue it would be great. Right now a single federated post may make the forum very slow for a period of time, and a single post + post edit can get the forum to a point where it shows nginx error screens to visitors.

Hey guys, if this is causing serious issues, I would note there a number of tools already in the plugin a community admin can use for this kind of scenario. There is comprehensive logging, including object logging, you can use to determine the source of any troublesome actors. activity_pub_verbose_logging activity_pub_object_logging The inbox and object retrieval has rate limiting and site settings you can use to control the rate at which requests are made. activity_pub_rate_limit_post_to_inbox_per_minute activity_pub_rate_limit_get_objects_per_minute There are site settings you can use for allowlist and blocklist of domains. activity_pub_allowed_request_origins activity_pub_blocked_request_origins There are admin actions you can use to “Reject” follows from problematic followers. Furthermore, the amount of activity a server can handle is going to be relative to the resources of a server. Something which I won’t have visibility over. @aschrijver I’d start with resources. What are the resources of the server? What exactly is being overloaded? I can’t even load socialhub.activitypub.rocks at all at the moment. I suspect there is a more fundamental issue with resource usage. Then, my second question would be where the requests are coming from? You can figure this out with the logs. Then add any domains you’re getting a lot of requests from to activity_pub_blocked_request_origins. If we’ve used those existing levers first, and we’re still seeing performance issues, then we can look at other potential causes.

Ok, SocialHub loaded, I fired up the logs and the culprit seems relatively clear. [Screenshot 2025-08-10 at 16.54.34] I’d suggest adding mastodon.sdf.org to the blocklist and sending a note to their admins that they’re spamming socialhub. *edit It seems another issue was that signed requests had been disabled. I’ve done the following: Set Activity pub require signed requests to true. Set Activity pub blocked request origins to mastodon.sdf.org. Let’s see if the issues persist.

No worries. I suspect simply enabling signed requests and adding mastodon.sdf.org to the blocklist is all that is needed.

[image] angus: I’d suggest adding mastodon.sdf.org to the blocklist It should block everywhere. It acts as a DDOS-agent. Amount of requests it does is totally horrible.

AP processing dragging forum down?

Product Support

aschrijver1 (Arnold Schrijver) August 10, 2025, 4:01pm 9

Thanks for your quick reply, @angus. I am just a regular member of this forum, but this looks to be useful info for @how or other forum admins to look into.

Topic		Replies	Views
How to debug connectivity issues with ActivityPub Administrators activitypub	22	937	January 27, 2025
Replies from the Fediverse not visible in Discourse: "Perhaps this topic was closed or deleted while you were looking at it?" Product Support activitypub	2	137	April 1, 2025
Local ActivityPub Actors are being created without keypairs Product Support activitypub	20	559	March 17, 2025
Activitypub returning null pages Bug activitypub	3	211	December 31, 2024
Why are supposedly ActivityPub-federated Discourse threads inaccessible via external AP clients? Bug activitypub	15	466	May 20, 2025

AP processing dragging forum down?

Related topics