If you think this post would be better suited in a different community, please let me know.


Topics could include (this list is not intending to be exhaustive — if you think something is relevant, then please don’t hesitate to share it):

  • Moderation
  • Handling of illegal content
  • Server structure (system requirements, configs, layouts, etc.)
  • Community transparency/communication
  • Server maintenance (updates, scaling, etc.)

Cross-posts
  1. https://sh.itjust.works/post/27913098
  • walden@sub.wetshaving.social
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    2 months ago

    We require applications, and most applications we get are extremely low effort and we don’t approve them. If you have open registrations you’ll be doing a lot of moderation for spam.

    Run the software that scans images for CSAM. It’s not perfect but it’s something. If your instance freely hosts whatever without any oversight, word will spread and all of a sudden you’re hosting all sorts of bad stuff. It’s not technically illegal if you don’t know about it, but I personally don’t want anything to do with that.

    • Dave@lemmy.nz
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      2 months ago

      I will add that if you have open registrations you will be a target for spam and trolls, and if you don’t take quick action then some other instances are likely to defederate from your instance.

      This depends on the instance, some will have a low tolerance and defederate pretty quickly, some instances will defederate temporarily until the spammers or trolls move to a different instance, and some won’t care. But you likely won’t know it’s happened unless you notice you aren’t getting content from that instance anymore.

      One other thing is that if you’re going to run an instance and aren’t already on Matrix, make an account. It’s how instance admins tend to keep in contact with each other.

      • Kalcifer@sh.itjust.worksOP
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        2 months ago

        […] if you’re going to run an instance and aren’t already on Matrix, make an account. It’s how instance admins tend to keep in contact with each other.

        This is good advice.

      • walden@sub.wetshaving.social
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        2 months ago

        It’s called Lemmy-Safety of Fedi-Safety depending on where you look.

        One thing to note, I wasn’t able to get it running on a VPS because it requires some sort of GPU.

        • Kalcifer@sh.itjust.worksOP
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          2 months ago

          One thing to note, I wasn’t able to get it running on a VPS because it requires some sort of GPU.

          This is good to know. I know that you can get a VPS with a GPU, but they’re usually rather pricey. I wonder if there’s one where the GPU’s are shared, and you only get billed by how much the GPU is used. So if there is an image upload, the GPU would kick on to check it, you get billed for that GPU time, then it turns off and waits for the next image upload.

          • pe1uca@lemmy.pe1uca.dev
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            2 months ago

            I don’t think there are services like that, since usually this means deploying and destructing an instance, which takes a few minutes (if you just turn off the instance you still get billed).
            Probably the best option would be to have a snapshot, which costs way less than the actual instance, and create from it each day or so yo run on the images since it was last destroyed.

            This is kind of what I do with my media collection, I process it on my main machine with a GPU, and then just serve it from a low-power one with Jellyfin.

            • Kalcifer@sh.itjust.worksOP
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              2 months ago

              create from it each day or so yo run on the images since it was last destroyed.

              Unfortunately, for this usecase, the GPU needs to be accessible in real time; there is a 10 second window when an image is posted for it to be processed [1].

              References
              1. “I just developed and deployed the first real-time protection for lemmy against CSAM!”. @db0@lemmy.dbzer0.com. !div0@lemmy.dbzer0.com. Divisions by zero. Published: 2023-09-20T08:38:09Z. Accessed: 2024-11-12T01:28Z. https://lemmy.dbzer0.com/post/4500908.
                • §“For lemmy admins:”

                  […]

                  • fedi-safety must run on a system with GPU. The reason for this is that lemmy provides just a 10-seconds grace period for each upload before it times out the upload regardless of the results. [1]

                  […]

              • db0@lemmy.dbzer0.com
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                2 months ago

                You can actually run it in async model without pictrs safety and just have it scan your newly uploaded images directly from storage. It just doesn’t prevent upload this way, just deletes them.

          • db0@lemmy.dbzer0.com
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            2 months ago

            The software is setup in such a way that you can run it on your pc if you have a local gpu. It only needs like 2 gb vram

            • Kalcifer@sh.itjust.worksOP
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              2 months ago

              That is a cool feature, but that would mean that all of the web traffic would get returned to my local network (assuming that the server is set up on a remote VPS), which I really don’t want to have happen. There is also the added downtime potential cause by the added point of failure of the GPU being hosted in a much more volatile environment (ie not, for example, a tier 3 data center).

              • db0@lemmy.dbzer0.com
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                2 months ago

                Not all web traffic, just the images to check. With any decent bandwidth, it shouldn’t be an issue for most. It also setup in such a way as to not cause a downtime if the checker goes down.

                • Kalcifer@sh.itjust.worksOP
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                  2 months ago

                  With any decent bandwidth, it shouldn’t be an issue for most.

                  It’s not only the bandwidth; I just fundamentally don’t relish the idea of public traffic being directed to my local network.

                • Kalcifer@sh.itjust.worksOP
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                  2 months ago

                  It also setup in such a way as to not cause a downtime if the checker goes down.

                  Oh? Would the fallback be that it simply doesn’t do a check? Or perhaps it could disable image uploads if the checker is down? Something else? Presumably, this would be configurable.

    • Kalcifer@sh.itjust.worksOP
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      2 months ago

      If your instance freely hosts whatever without any oversight, word will spread and all of a sudden you’re hosting all sorts of bad stuff. It’s not technically illegal if you don’t know about it, but I personally don’t want anything to do with that.

      Yeah, this is my primary concern. I’m hoping that there are established best practices for handling the majority of this sort of unwanted content.

      • Dave@lemmy.nz
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        2 months ago

        The spam is not from bots, it’s people being paid to spam. Captchas absolutely need to be turned on or else you get bots as well, but they don’t stop the spam.

        • Kalcifer@sh.itjust.worksOP
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          2 months ago

          The spam is not from bots, it’s people being paid to spam.

          Do you know any specific/official organizations that do this, and/or examples where it’s occured on Lemmy?

          • Dave@lemmy.nz
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            2 months ago

            Its pretty random outside the Russian misinformation sites (which I haven’t seen in a while, but they probably got better at hiding).

            Its hard to give you a link because mods or admins remove the posts or ban the accounts pretty quick most of the time. But there is a new spam account at least every day (I can think of at least two today. Edit: 4). They come in waves so sometimes there are a whole bunch.

            That’s probably another thing you need to know. I’m on Lemmy.nz, you’re on sh.it.works. If some new spam account signs up on Lemmy.world and posts to lemm.ee, then if it’s removed by an admin on your instance it is only removed for people on your instance. Everyone else still sees it as your instance is not hosting either the community or the user so it can’t federate our anything to deal with it. The lemm.ee instance could remove the post or comment with the spam in a way that federates out to other instances, but can’t ban the user except for on their instance. Only the Lemmy.world instance can ban the user in a way that federates out to other instances. This is something you’ll get a better understanding of over time.

            Lemmy.world has a lot if help so they don’t have issues, but often the spam will come from obscure instances while the admin is asleep and there is no backup, so every other instance has to remove the spam for their own instance. Then you have to work out how to mitigate that for your own instance when you are asleep. Most admins are pretty understanding that this is a hobby and don’t expect everyone to be immediately available, but if you have open registrations then you are likely to be targeted more and need a better plan.

            • Kalcifer@sh.itjust.worksOP
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              2 months ago

              If some new spam account signs up on Lemmy.world and posts to lemm.ee, then if it’s removed by an admin on your instance it is only removed for people on your instance. Everyone else still sees it as your instance is not hosting either the community or the user so it can’t federate our anything to deal with it. The lemm.ee instance could remove the post or comment with the spam in a way that federates out to other instances, but can’t ban the user except for on their instance. Only the Lemmy.world instance can ban the user in a way that federates out to other instances.

              This make me think that we should maintain a community curated blocklist in, for example, a Git repository. It could be a list of usernames, and/or a list of instances that are known to be spam that gets updated as new accounts and instances are discovered. Then any instance owner can simply pull the most current version of the blocklist (this could even be done automatically). Once the originating instance blocks the malicious account, they can be removed from the list. This also gives those who have been blocked a centralized method to appeal the block (eg open an issue to create an appeal).

              I would honestly have expected something like this to already exist. I think it’s partly the purpose of Fediseer, but I’m not completely sure.

              • Dave@lemmy.nz
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                2 months ago

                This make me think that we should maintain a community curated blocklist in, for example, a Git repository.

                There would be a few problems I can think of with this approach. The first one is who controls it? Whoever that is, you haven’t solved the issue because now instead of only the instance with the user being able to federate the ban now only the maintainer of the git repo can update the ban list.

                If you have many people able to update the repo, then the issue becomes a question of how do you trust all these people to never, ever, ever get it wrong? If you ban a user and opt to remove all their content (which you should, with spam), then if you are automating this you end up with the issue of if anyone screws up then how do you get someone’s account unbanned on all those instances? How do you get all their content restored, which is a separate thing and Lemmy currently provides no good way to do this. How do you ensure there are no malicious people with control of the repo but also have enough instances involved to make it worthwhile?

                There is a chat room where instance admins share details of spam accounts, and it’s about the best we have for Lemmy at the moment (it works quite well, really, because everyone can be instantly notified but also make their own decisions about who to ban or if something is spam or allowed on their instance - because it’s pretty common that things are not black and white).

                I would honestly have expected something like this to already exist. I think it’s partly the purpose of Fediseer, but I’m not completely sure.

                Fediseer has a similar purpose but it’s a little different. So far we have been talking about spam accounts set up on various instances, and the time it takes for those mods and admins to remove the spam. But what happens if instead of someone setting up a spam account on an existing instance, they instead create their own instance purely for spamming other instances?

                Fediseer provides a web of trust. An instance receives a guarantee from another instance. That instance then guarantees another instance. It creates a web of trust starting from some known good instances. Then if you wish you can choose to have your lemmy instance only federate with instances that have been guaranteed by another instance. Spam instances can’t guarantee each other, because they need an instance that is already part of the web to guarantee them, and instances won’t do that because they risk their own place in the web if they falsely guarantee another instances (say, if one instance keeps guaranteeing new instances that turn out to be spam, they will quickly lose their own guarantee).

                Fediseer actually goes further than this, allowing instances to endorse or censure other instances and you can set up your instance to only federate with instances that haven’t been censured or defederate from instances that others have censured for specific reasons (e.g. “hate speech”, “racism”, etc).

                It’s quite a cool tool but doesn’t help the original discussion issue of spam accounts being set up on legitimate instances.

    • Kalcifer@sh.itjust.worksOP
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      2 months ago

      We require applications

      Is this functionality built into the Lemmy software?


      Addendum (2024-11-11T00:32Z):

      Ah, yeah, it looks like it is configurable in the admin panel [1].

      References
      1. Lemmy Documentation. join-lemmy.org. Accessed: 2024-11-11T00:35Z. https://join-lemmy.org/docs/users/01-getting-started.html#registration.
        • “2. Getting Started”. §“Registration”.

          Question/Answer: Instance admins can set an arbitrary question which needs to be answered in order to create an account. This is often used to prevent spam bots from signing up. After submitting the form, you will need to wait for some time until the answer is approved manually before you can login.

      • walden@sub.wetshaving.social
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        2 months ago

        Yeah, it’s just something like “Tell us why you want to join this instance”. If the answer is “to promote my content” or “qq”, for example, they don’t get approved.

        It’s done by the Lemmy software.

    • catloaf@lemm.ee
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      2 months ago

      I would just turn off media uploads entirely. It’s not worth the risk or disk space.

      • Kalcifer@sh.itjust.worksOP
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        2 months ago

        I would just turn off media uploads entirely.

        Do you mean also disabling thumbnails? IIUC, pict-rs handles all thumbnail generation [1]. The reason I point this out is that simply disabling image uploads won’t itself stop the generation of thumbnails [2]. There’s also the question of storing/caching images that come from federated servers.

        Referencs
        1. Lemmy Documentation. Accessed: 2024-11-11T01:59Z. https://join-lemmy.org/docs/administration/administration.html.
          • “9. Administration”. §“Lemmy Components”. §“Pict-rs”.

            Pict-rs is a service which does image processing. It handles user-uploaded images as well as downloading thumbnails for external images.

        2. “I just developed and deployed the first real-time protection for lemmy against CSAM!”. @db0@lemmy.dbzer0.com. Published: 2023-09-20T01:38:09-07:00. Accessed: 2024-11-11T02:16Z. https://lemmy.dbzer0.com/post/4500908.
          • ¶1

            […] if the content is a link to an external site, lemmy sill caches the thumbnail and stores it in the local pict-rs […].