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Comment by marginalia_nu | Hacker News Reader

This is a tangent. I must have been maybe 15-16 at the time, so somewhere around 20 years ago: One of the first pieces of software I remember building was a POP3 server that served files, that you could download using an email client where they would show up as attachments.

Incredibly bizarre idea. I'm not sure who I thought would benefit from this. I guess I got swept up in RFC1939 and needed to build... something.

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On my first job (in the beginning of the millennium) there was a limit on files you could download, something around 5Mb. If you wanted to download something bigger, you had to ask sysadmins to do that and wait... That was really annoying. So I and my colleague end up writing a service, that could download a file to local storage and chop it into multiple 5Mb attachments and send multiple emails to requestor.

After some time the limit on single file was removed, but daily limit was set up to 100Mb. The trick is that POP3 traffic wasn't accountable, so we continued to use our "service".

That sounds suspiciously similar to how I used to download large files on a shared 2GB/month data plan. My carrier didn't count incoming MMS messages towards the quota, and conveniently didn't re-encode images sent to their subscribers via their email-to-MMS gateway. So naturally, I'd SSH into my server, download what I wanted to download, and run the bash script I wrote, which split the downloaded file into MMS-sized chunks, and prepended a 1x1 PNG image to them, and then sent them sequentially through my carrier's gateway. This worked surprisingly well, and I had a script on my phone which would extract the original file from the sequence of "photos". It may still work, but I've since gotten a less restrictive data plan.

I couldn't download .exe files at some $CORPORATION. They had to be whitelisted or something, and the download just wouldn't work otherwise. But once you had the .exe you could run it just fine. You just had to ping some IT person to be able to retrieve your .exe.

Of course it was still possible to browse the internet and visualize arbitrary text, so splitting the .exe into base64-encoded chunks and uploading them on GitHub from another computer was working perfectly fine... I briefly argued against these measures, given how unlikely they are to prevent any kind of threat, but they're probably still in place.

We still cannot email each other .py files where I work. But .py.txt is of course fine...

apparently e-mail is not much reliable for storing/keeping files. there have been cases where an old email with an attachment would not load correctly because the servers just erased the attachment file.

This was a custom email server though, there never were any emails, it just presented files as though they were so that a client would download them.

Actually caused some problems for email clients, as they usually assumed emails were small. I got a few of them to crash with 200 Mb "attachments" (although this was in the early 00s, 200Mb was bigger than it is today).

I'm still confused on how this worked, did you email some address and get a reply with the attachment ?

Since GP says it was a POP3 server, I suppose you would set up an email account in your client with its inbox server pointing to that POP3 server. When the client requests the content of the inbox, the server responds with a list of "emails" that are really just files with some email header slapped on; so your email client's inbox window essentially becomes a file browser.

Yeah, that's basically it.

Interestingly, if you take a look at your emails from a few years ago, most of the non attached images will fail to load now.

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