this post was submitted on 20 Oct 2026
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I shared a link from NPR Tiny Desk but there was no image preview or video embed. After investigating this I learned that when you do that, each instance picks up the link and individually retrieves the link preview nearly simultaneously. For gargantuan sites like YT or Reddit, this is a trivial amount of traffic and not a problem, but for smaller sites like NPR this results in a sort of botnet DDOS attack on the site's servers. More here. Another example here . For that reason, NPR has blocked Fediverse servers like Mastodon.

I have experienced this on my personal server as well (DDOS), but at the time didn't know why, exactly.

This isn't the end of the world, but certainly is not great and hurts engagement with the content. Is there a solution for this? Perhaps using some sort of webtorrent service like PeerTube where they just fetch the information from another fediverse server instead of the source server? Maybe fetching embeds client-side? At least that would stagger the requests.

E: Many people have replied comparing this to the Reddit "hug of death" or "The Slashdot effect". This is not the same at all. Those are legitimate site visits from humans that happen over the course of several hours. This is the result of several thousand servers all automatically fetching the same image simultaneously , and without any human involvement, and potentially next to zero human traffic to the site, which is why I compared it to a botnet or DDOS attack.

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[–] LovableSidekick@lemmy.world 4 points 2 days ago (1 children)

I remember reading the same thing about reddit, slashdot, fark, and other sites. But I like the FASP idea as a way to relieve this.

[–] artyom@piefed.social 1 points 2 days ago (1 children)

Why is that? Those are centralized platforms, they should only need to retrieve the preview once each?

[–] INeedMana@piefed.zip 3 points 1 day ago (1 children)

https://en.wikipedia.org/wiki/Slashdot_effect but people were going in, looking at the link, sometimes overwhelming the server

[–] artyom@piefed.social 3 points 1 day ago (1 children)

That's not at all the same thing. That's just the inability to handle large amounts of unexpected normal user traffic.

This is essentially bot traffic driven by servers all independently but simultaneously fetching the same image, without even a single human necessarily looking at it.

[–] INeedMana@piefed.zip 5 points 1 day ago (2 children)

From server's perspective the only difference between those is the user-agent. Traffic is the same

[–] HereIAm@lemmy.world 5 points 1 day ago (1 children)

But what OP is talking about is a technical detail that can be fixed.

[–] INeedMana@piefed.zip 3 points 1 day ago* (last edited 1 day ago)

Yes, but then a comment mentioned the "hug of death" - high spike of requests resulting from a link being shared on some site, and OP asked why centralized sites were also creating problems

There was another post regarding previews some months/(knowing me probably a year) ago and personally I would go with federating previews. With a button for mods to refresh it from source for when something goes fucky

But social networks have been creating random bursts of requests, this way or another, even in the times of centralized socials

[–] artyom@piefed.social 1 points 1 day ago

The origin and purpose of the traffic is not the same. That's why they block one and not the other.

[–] ieightpi@lemmy.world 4 points 2 days ago (2 children)

This probably why my place of work blocked it behind the firewall

[–] artyom@piefed.social 2 points 2 days ago* (last edited 2 days ago) (1 children)

Do they block the useragent or the URL? NPR apparently blocks the former.

[–] Ghoelian@piefed.social 3 points 1 day ago (1 children)

You're talking about 2 different kinds of blocking here. NPR can't block a URL, that concept doesn't really exist at this level. They could block ip addresses, or user agents as you mentioned.

A workplace can't block by user agent (at least not on any website using TLS), as this header is not readable by any intermediary devices.

[–] artyom@piefed.social 0 points 1 day ago (1 children)

NPR can't block a URL

I wasn't talking about NPR, I was talking about their employer...

[–] Ghoelian@piefed.social 1 points 1 day ago* (last edited 1 day ago)

You mentioned both in the same comment...

[...] NPR apparently blocks the former

I'm just saying, their employer can't block like NPR does, because they are fundamentally different things. The one is a server receiving a request, the other is a firewall seeing encrypted packets.

Edit: the other could also be a DNS resolver that just does not resolve certain domains.

[–] Hegar@fedia.io 1 points 2 days ago

This was my first thought too.

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