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Ask Slashdot: Why Haven't They Increased Size Limits for Email Attachments? 260

"Email system are quite capable of sending and receiving large attachments," writes long-term Slashdot reader Stonefish "However, size limits are generally tiny."

And then he tells a story... In the late 1990s I worked for a research organisation maintaining their mail system, and had recently introduced mail size constraints. Within the first day it had blocked a number of emails — including a 700MB attachment.

Being a master of all thing Internet I called up the sender to tell him firstly how such a large email would cause problems for the receiver, and secondly how there were far more efficient ways of sending things. Given that he was on the same campus he invited me down to his lab to discuss this further. (After showing me round his lab, which was pretty impressive apart from the large "Biohazard" and "Radioactive" materials labels on the doors.) He told me that the facility he was sending the attachments to was a supercomputing hub with similar "Fat" pipes to the Internet so the large emails weren't a problem. I then spoke about the "efficiency" of the mail protocol and he said that he'd show me what efficient was and did a quick, "drag, drop and send" of another 700MB file of his latest research results.

He was right, I was wrong, it was efficient from his perspective and all his previous emails were easily available demonstrating when and where they were sent. As a result of this we changed our architecture and bought bulk cheap storage for email as it was a cheap, searchable and business focused approach to communications.

However 20 years plus later, even though networks are tens of thousands of times faster and storage is tens of thousands of times cheaper — email size limits remain about the same. Email remains cheap, efficient and ubiquitous — but we expect people to upload a file to a site and generate a link and embed in a manner that means we lose control of our data or it disappears in 12 months.

What's missing from this analysis? (Wikipedia's page on email attachments notes the intermediate "mail transfer agents" that store and forward email "and may therefore also impose size limits.") But even that page admits some attachment limits are arbitrary.

I always assumed it was an anti-piracy measure. Anyone know the real answer? Share your own thoughts in the comments.

Why haven't they increased size limits for email attachments?
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Ask Slashdot: Why Haven't They Increased Size Limits for Email Attachments?

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  • by NateFromMich ( 6359610 ) on Saturday June 04, 2022 @07:18PM (#62593340)
    Like, some idiot emails a 700mb file to staff@place.com and now there are 500 people with a copy of it, half of them pulling it into their phone over LTE, wondering what's up.
    Meanwhile, their mail server is choking and out of storage space.

    Just because you have gigabytes of space on your desktop and a 1g fiber connection, doesn't mean giant emails are a good idea.

    • If you are running a business with less storage and slower network connection than my home computer, then *YOU* are the problem.
      • Your 350 terabyte email is not trivial...
        • I believe this is the problem. MS and other email server providers have reasonable chain mail protection now, but even 6 years ago BP's enterprise email was brought down by email storms.

          The bigger problem is that while large email attachments aren't a technical challenge, the universes' propensity to create better morons outpaces storage and the capabilities of the email client. For example, using a +50gb PST/OST file is going to require constant consistency scanning. Users won't do that, they will make a
          • by narcc ( 412956 )

            Google offers a more intelligent scheme that automatically converts email attachments over 25gb to Google Drive files with links that permit "many to one".

            Which sucks and confuses recipients. Now, this might be okay if there was some standard that email clients could follow to make those links look and act link normal attachments.

            Let one of the big players do it and the rest will follow -- like the html email plague.

          • One day MS will copy this feature.

            Christ I hope not, it is a fucking awful feature that assumes the end recipent has the connectivity and ability to download them. Any cunt dumb enough to email a 25gb+ attachment should be blocked not enabled.

      • by Mascot ( 120795 )

        Where I live, our corporate 100Mbit connection costs about 10 times what I pay for 1Gbit at home. I haven't even bothered asking what they'd charge for corporate gigabit, because we just don't need it.

        Not many companies would want to deal with the storage requirements of people sending hundreds of megabytes worth of attachments to their 200 favorite colleagues. You put that on a damn fileshare and let them know where. If they're documents, you check them into the document management system and tell people a

        • by Kremmy ( 793693 )
          Where I live, our corporate 100Mbit connection costs about 10 times what I pay for 1Gbit at home

          There are a few reasons for that. The leased line is a dedicated link for the corporation, not a neighborhood shared endpoint. It is often symmetrical, being that it's 100Mbps in both directions and being a leased line there might actually be contract verbiage specifying that it actually provides that capacity in full. Your 1Gbit home connection probably doesn't have gigabit upstream. It might not even have b
          • The price difference between commercial and residential ISP service is the difference between "dedicated" and "shared" bandwidth, as well as "service level commitment" and "best effort" bandwidth obligations.

            I have a very reasonably-priced business account at my house, it allowed me to have 5 static IPs for just a few extra bucks/month.

        • Your home 1Gbit is actually a shared bandwidth with no guarantee of 1Gbit at any particular point in time, ISP, massively overprovision as that is the only way they can make those home connections affordable and most of the time you and others are only using a fraction of the available bandiwdth anyway. The corporate 100Mbit will be a true 100Mbit symmetrical connection all the time.
          • by Mascot ( 120795 )

            Your home 1Gbit is actually a shared bandwidth with no guarantee of 1Gbit at any particular point in time, ISP, massively overprovision as that is the only way they can make those home connections affordable and most of the time you and others are only using a fraction of the available bandiwdth anyway. The corporate 100Mbit will be a true 100Mbit symmetrical connection all the time.

            I believe this is true in the US, but it is not here in Norway. Actually, I can't say for sure that it isn't contractually true in some ways. It's possible they technically overprovision home users in that they would not be able to give _everyone_ a gigabit at the same time. On the other hand, if that is the case, then they only overprovision to the point where no one is actually able to notice. As in, even during extreme peaks they are still able to give everyone what they paid for. An ISP that did not sup

      • by lsllll ( 830002 )
        You do realize that a business Internet connection is NOTHING like a home connection, right? The SLA is completely different (Onsite in 4 hours and stay until it's fixed, at least for me). The guaranteed up/down rates are, well, guaranteed. You actually get some address space, be it 5 IPs of 100, and they're static, not DHCP, like your home connection. And to a business the up rate is just as important than the down rate, not like a home connection. And nothing is filtered or blocked on a business inte
  • by retchdog ( 1319261 ) on Saturday June 04, 2022 @07:24PM (#62593354) Journal

    email exists mostly to keep a formal record (or at least define what a "formal record" is, since everything is just electricity/magnetism anyway) or to interact with external clients.

    in your example, the professor was using email because it was the easiest and simplest thing he had that let him send a file and keep a record of it. the thing is, most places have a solution to that now; the standard protocol is to store the file wherever and then send a link, and, yes, this is actually an improvement over emailing ad-hoc chunks.

    to answer your question: email became a stopgap solution to many things that are now solved differently, and it turns out that once those things are solved, you don't really need email attachments apart from a few corner cases which don't usually require ginormous send limits.

    tl;dr: dropbox, slack, onedrive, google drive, etc. do what email attachments used to do, but better, so no one cares.

    • Is dropbox actually still around? Haven't onedrive and google drive been reducing their storage limits, lately?

      Isn't it just a lot easier to just email an attachment? Does that somehow seem difficult to you? You drag and drop, and suddenly it's an awkward labeled base64 package that everyone knows how to encode, transmit, receive, and decode.

      If you're complaining about bandwidth or drive space, grandpa, this is not 1980.

      • i'm referring to the business case, where the use limits are generally whatever the firm pays for.

        easier to email an attachment: eh, kinda? it's about the same truth be told. but the problem with emailing attachments isn't, uh, emailing attachments; the problem is version control. everyone ends up with different versions of the file and no obvious way to reconcile them and this sucks. for this we have git (for programs) and document version tracking (for documents), and they are amazing tools.

        i'm not compla

      • by mysidia ( 191772 )

        If you're complaining about bandwidth or drive space, grandpa, this is not 1980.

        These are perfectly valid obstacles against large attachments.
        Bandwidth and Drive space are Not and will never be free.

        Large attachments are in fact HIGHLY inefficient in both these respects and operationally for mail servers - the Professor's argument of measuring efficiency is Bogus, since they considered Only their personal human efficiency in terms of their own unique personal workflow.

        A 700 Megabyte email to 10 re

        • by tepples ( 727027 )

          Do you recommend anything in particular for replacing attachments, particularly other than for files sent within a corporation? Should all major email clients implement all major file host services' upload protocols?

          • by mysidia ( 191772 )

            Do you recommend anything in particular for replacing attachments ..

            It seems to have become customary for the email service provider to provide this alongside their email Offering, for example Microsoft Office365 / Outlook.com users get OneDrive and it's Integrated within Outlook so it gives the option to automatically upload and/or share the link directly from the Email software.

            Google's Google Workspace / Gmail services do the same with Google Drive Integration.

            The "attachment limitation" is b

    • by splutty ( 43475 ) on Saturday June 04, 2022 @08:35PM (#62593508)

      How many of your options support Linux/VAX/IBM Mainframes? How many of your options are not run by companies that you should really not trust with your sensitive data?

      From a user point of view, just attaching a file to an email is *still* the easiest and most 'logical' way. No matter what admins like us think about that.

    • Email is an excellent way to send information asynchronously, allowing for efficient multitasking, without having to talk or chat with people on demand. People who use email correctly can save tons of their time and other people's time. Those who use it poorly are doomed to recreated the same problems in the apps that replace it. Email has been declared obsolete and replaced with Teams and Slack, etc., which are basically just chat and phone, and now people ignore it as much as they did email, so I guess

  • by houstonbofh ( 602064 ) on Saturday June 04, 2022 @07:29PM (#62593366)
    The classic mail servers do not have de-duplication. So a reply all with a 500 meg attachment can be terabytes of data in a large company. Also, many companies have data retention policies on email, and large attachments can make that very expensive.
    • Don't just think about back end infrastructure challenges. Those are solvable fairly easily.

      Think about end user computers. If everyone is forwarding around gig email files, how much storage is going to be required on their computer? I have had many difficult executives and their assistants who refuse to delete email, ever, and who want every email from the dawn of time to be permanently accessible instantly from their computer - there is no time to wait for that 500 page deck to download from 5 years ago w

  • Thank goodness! (Score:5, Insightful)

    by Alworx ( 885008 ) on Saturday June 04, 2022 @07:32PM (#62593380) Homepage

    I think current limits are fine, given the push nature of email and how arbitrarily you can send a message to anyone (aka spam) without consent.

    With cloud based storage taking over, attachments could almost be done with altogether, in favour of live/snapshot links. But that would be too draconian :-)

  • Because SPAM (Score:2, Interesting)

    by Gabest ( 852807 )

    But not because spam is big. Private SMTP servers are basically not allowed anywhere on the internet, you MUST have an account at a well known service like gmail. And gmail is only free up to 15GB.

    • Re:Because SPAM (Score:4, Insightful)

      by glum64 ( 8102266 ) on Saturday June 04, 2022 @08:13PM (#62593474)
      You are terribly misinformed. I run a private e-mail service for my family for at least 20 years, well before Gmail and other behemoths became a thing. It is (D)DoS that really worries operators of any service, not only mail.
      • by tepples ( 727027 )

        Welcome to the world of IPv4 address reputation, where not even valid SPF, DKIM, and DMARC will keep a newly established mail server's messages from getting discarded.

      • And you haven't kept up to date. I've also run my own e-mail for about 25 years, and today hardly any major servers on the Internet will communicate with my bitty little e-mail sever, because they don't recognize me as a major corporation. As the years have gone by, more and more often, messages sent to me never show up, and messages I send never reach their destination and I never receive any bounce errors. There's no law that says anyone HAS to forward to your server, and... often they just don't.

        Thank

    • WTF? this is supposed to be a technical oriented forum, how could something so blatantly incorrect get modded up? I guess I should shutdown my Prvate SMTP server as it can't possibly be working.
      • Yeah, this has long been a place where nonsense is modded up.
        Look at the question posed by this story. Any admin of any kind, or even a reasonable knowledgeable office worker can answer why this is a stupid idea.
      • > I guess I should shutdown my Prvate SMTP server

        Deep breath. People are wrong on the Internet.

        Anyone single-sourcing opinion online is going to have a bad time.

        That said, a good postfix howto for fielding a new ip would be welcome.

        And it's a minefield in 2022 to do mail right. Back in the 80's somebody would just hack up some m4 to keep up with reality and post it in a comp.* group. Now it'll take ten years and a committee.

    • Private SMTP servers are basically not allowed anywhere on the internet....

      I have been running private email servers for about 16 years now. Initially it was on my DSL line, but there were ToS and other reasons I stopped doing that.

      I rent a couple cheap private servers ($12/month each), and run Postfix on them. I have had no problems. The only reasons I have a gmail account are because I've had it since gmail was invitation-only (and I like being able to say that), and I use Google services that require a Google account. Nothing of importance goes through it. Otherwise I have no u

    • by splutty ( 43475 )

      An SMTP server is an SMTP server. There is no such thing as a "Private SMTP Server".

  • by DavidinAla ( 639952 ) on Saturday June 04, 2022 @07:38PM (#62593394)
    I use Apple's iCloud email and I'm happy with the way it handles attachments. When I send a large attachment, the attachment is simply uploaded to an Apple server. When the recipient gets the email, there's a link (where the file icon would be) to download the attachment, which also tells the size of the file. For me, this makes it pretty transparent for the user, regardless of the file size limitations placed on the recipient's end.
  • Both email clients and the people that use them are dumb.

    1. First of all, email clients generally download everything immediately when you check for mail. "But I use a webmail service" which means that service doesn't want to store your oversized emails indefinitely because you refuse to delete old email.

    2. People are stupid and try to email video attachments of uncompressed audio/video files which clock in at 400MB/minute when the truth is that a highly compressed mpeg4 file could have done the job at a l

    • by vakuona ( 788200 )

      I think clever integration of "drop box" like file storage with a mail service could address most of the issues raised here.

      In any case, for (1), if you have an overall mail box size limit, then it doesn't really matter if some emails are large. Large emails are probably stored more efficiently than many small emails anyway.

      For (2), you could still allow a much larger limit, just not the typical 10-20MB. And also, your mail service could do that for you anyway, so you don't have to think about it.

      • by tepples ( 727027 )

        I think clever integration of "drop box" like file storage with a mail service could address most of the issues raised here.

        With how many brands of "'drop box' like file storage" must each mail client integrate?

  • Even on a fairly recent machine you will notice the lag in converting a 700MB BASE64 email into the original binary. This encoding also further increases the size.

    Because of this BASE64 encoding the attachments are also mostly inseparable from the text email they are attached to. All this would be solved if there was a way to upload an attachment to a SMTP server separate to the email in binary format. On the recipient side it could be accessed by reference rather than as part of the message body.

    Som
    • This is a case of those who refuse to learn from the mistakes of history are doomed to repeat them. None of those options are good, for a litany of reasons.

  • Push (Score:5, Interesting)

    by markdavis ( 642305 ) on Saturday June 04, 2022 @07:43PM (#62593408)

    >"Why haven't they increased size limits for email attachments?"

    Because Email isn't something you CHOOSE to receive. It really is that simple. As a sysadmin, you don't want to allow riffraff to push gigabytes of crap to all of your users. Not only could it potentially eat up all your bandwidth, but so many users care nothing about storage (and in the enterprise, secure and reliable/backed up storage can be costly). A single 500MB attachment sent to a great number of your users could chew up hundreds of GB of space. And users are notorious about never cleaning up their Email. And then there is spam...

    Email is more about messaging, not file transfer. There are other services you can link the file to for which the Email is just the notification. Plus Email was never designed to be secure (and mostly still isn't).

  • Because you'll start sending everything through email, and you will never delete any of it. The storage demands will be ever growing for historical things you'll never look at again.

    What is reasonable? What if your mailbox was limited to 10G, and the biggest email you could send was 10G, but that would fill up your mailbox all at once? How long do you expect it to take to send your 10G email?

    I have a coworker with a 50G active mailbox. She has about another 80G in older archived mail. She keeps everything

    • And all of those attachments are now stored in both email and in file systems outside of email. Email is not a backup system.

      • This would be like keeping all of your physical mail, forever.
        For that matter, the original question is like asking why residential mailboxes aren't all the size of a warehouse so you can just drop pallets off at any address.
  • by bloodhawk ( 813939 ) on Saturday June 04, 2022 @07:46PM (#62593418)
    Seriously is the article writer a moron? it isn't obvious why limits are there? tell ya what , turn your limits up and post a email server address, betting the server won't last a day. Even internally at enterprises I have seen the entire email infrastructure collapse because some idiot decided to send videios out to half the company and they had no limits internally.
    • Agreed. Raising this as a question or topic of discussion at all isn't much different than if I asked the forum why they don't allow us to hang candles upside down in light sockets â¦
  • Seriously, half my organization put a company logo at the end of their emails. That logo is 3MB large. They send email invitation to event as 15MB jpg. Don't give them more power to do stupid things!

    • To: original sender
      Cc: original recipients
      Subject: Re: something everyone on this list should know about

      Please take me off this mailing list. Thanks

      [another 3MB jpeg logo]

      > hey here's something everyone on this mailing list should know about!
      > [original 3MB jpeg logo that went out to everyone]

  • by Anonymous Coward

    1. Encoding is crap. For legacy compatibility reasons the best email attachment encoding available is base64, where each 3 bytes block of source data gets converted to 4 characters, so suddenly your 700MB attachment is 931MB of MIME encoded email data.

    2. There's no de-duplication. If you send an email to all@example.com then suddenly the 1,000 or so mailboxes residing at example.com each have their own copy of your 931MB email, causing a sudden 931GB jump in mail storage utilization.

    3. Because email isn't s

  • by ilsaloving ( 1534307 ) on Saturday June 04, 2022 @08:08PM (#62593462)

    As someone who has had to manage these things, I can give you a very simple answer:

    Our email server is not your personal file server. When large file attachments are allowed, people use email to do all their file transferring, which consumes a staggaring of storage space AND network.

    And of course they won't delete those emails afterwards, and then when people's quotas fill up they tear help desk a new one for preventing them from doing what they "paid for" and demand larger quotas.

    Email is for exactly that: Email.

    If you want to transfer large files, there are a bajillion systems you can use as an alternative.

  • by skinlayers ( 621258 ) on Saturday June 04, 2022 @08:14PM (#62593476)

    Slashdot's quality is really dropping these days. Email attachments were a hack that were never part of the original spec. You literally take binary data and encode it as text (which takes up more space than the original binary file) so it can piggyback on the email. We used to have problems all the time with large email attachments failing to send and backing up users outboxes. Come on, this is basic stuff, people!

  • GMail doesn't even bother and sends you to Google Drive when trying to send files larger than 20 megabytes, even on Google Workspace/G Suite.

    What is this, 1998?

  • I've seen just how bogged down a mail server can get when someone sends even a 20MB attachment to all 1000+ people who have a departmental email account...

  • ... after a mad spam gang with a large botnet Joe-Jobs you with messages carrying huge attachments.

  • This is the real question. Outlook is based on the IE 6 browser engine, and even then is was bastardized. Email should support a subset of HTML5 with CSS3 to allow for proper responsive design and modern layouts.

    Large attachments I can do without. I'd much rather just add the file to my drive instead of having to download the file, then just move it back to the cloud.

  • by kmoser ( 1469707 ) on Saturday June 04, 2022 @11:25PM (#62593760)
    Sysadmins set limits based on, among other things, business rules and available storage space. This varies widely between businesses (and sysadmins). If you don't like it, run your own mail server. They you can't complain about what "they" do, since "they" will be *you*.
  • Living in a rural area, I have internet limitations. My satellite internet has a 10 GB/month data cap. My crappy wireless internet runs at 3 megabits/second maximum. If someone sent a large file to me, it'd work against my data cap or with my other internet service, it'd take hours to download.

    We don't all live in a city with a fast internet infrastructure.

    (FWIW, I'e been on the Starlink waiting list for about a year and it may take another one before I even get close to having it)

  • Once Email became common enough that everyone had heard of it, and knew it was a form of corporate communications, the lawyers started to subpoena emails when doing discovery for a lawsuit. An email system that allows 700MB file attachments just has too much liability associated with it. That's 700MB of evidence against the CEO of wrongdoing, PER EMAIL! So companies instituted Email retention policies so that the evidence cannot be kept for more than a year, and then it's just automatically deleted, so as n

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