John, I agree completely with everything you say here. Ned > --On Thursday, March 15, 2012 08:16 -0700 Ned Freed > <ned.freed@xxxxxxxxxxx> wrote: > >... > >> > It might be okay for really large attachments, as long as > >> > only a few messages are affected. > > > >> Borrowing a bit from Randy, the solution to really large > >> attachments is to ban them. Personally, I'd find it perfectly > >> reasonable to have any message in the megabyte range or above > >> (or probably even an order of magnitude smaller) rejected > >> with a message that amounted to "if you have that much to > >> say, write an I-D, post it, and point to it". That is much > >> more plausible today, when the mean time between I-D > >> submission and posting is measured in minutes (except during > >> blackout periods) than when it was in days. During blackout > >> periods, the last thing the community needs is people adding > >> to already-overloaded lists by posting long documents in > >> email. > >... > > You begin by talking about "banning large attachments". You > > then segue into a discussion where you talk about a maximum > > size that includes the primary message content, not > > attachments, then you throw in disclaimers, which may or may > > not be attachments. > > > > Other have followed up by supporting the limit on attachment > > size, others still have talked about banning attachments > > regardless of size. > > > > Do you see the problem here? The minute you start focusing on > > specifics of message content, you're in a rathole. What counts > > as an attachment? (And yes, we have a precise definition for > > what constitutes an attachement, but following that definition > > gives people the ability to route around it.) > Ok, that is fair. At best, I skipped being explicit about > several steps in my thinking. I personally see the attachment > issue as almost irrelevant, in part because of the "what > constitutes an attachment" issue you identify above. In partial > defense, I was distracted a bit by comments from others about > "the first N bytes of a message" and "text and attachment" > models (which, as you know better than almost anyone, is a user > construct about how messages might be assembled but one that > doesn't necessarily map directly and usefully back from MIME > body parts). > I think the issue is almost entirely about > (i) size, independent of how a message is structured, and > (ii) what, in IMAP terms, is automatic synchronization > into offline or disconnected mode. More generally, it > is ability to read and work with IETF mailing lists at a > time when one has little or no connectivity. > >From that point of view, Russ's original question is about > something that is not only a bad idea but an ill-formed > proposition... at least unless we could agree on and enforce a > particular model of IETF participants assemble messages and send > them -- a goal that I believe is so hopeless as to not be worth > discussing. > > It follows that any limit needs to be on overall message size. > > (Even this is a little perilous because message sizes can > > change due to MIME downgrading or upgrading, both of which > > happen regularly.) > Exactly. And that also identifies the other distraction I was > trying to get at. In addition to MIME downgrading and > upgrading, the size of a message can be distorted by such things > as addition (possibly by submission servers or list exploders > and out of user control) of lengthy explanatory headers > (including some called for by IETF standards like DKIM), body > text (including the notorious "unless you agree to this > conditions, please un-read the message" announcements but all > list-added footers), or duplicate content (e.g., sending both > text/plain and text/html with multipart/alternative). If we > were to start trying to split hairs on how to count message > sizes, I think we would rapidly go down a slightly different rat > hole. > > I would not be opposed to imposing such a > > limit, although it's going to need to be higher than some > > people would probably like - it's surprising how easily you > > can approach 1Mb with a single part, plain text message > > containing nothing remotely resembling an "attachment". > Yes. But an entirely anecdotal survey of recent postings to the > IETF list and comparison with Thomas Narten's statistics > indicates that a posting to that list of 50K in aggregate size > is well out on the upper tail. Most messages of twice that size > and larger are either duplicate content or inclusion of a great > deal of content from multiple previous messages. I'd be happy > discouraging both of those patterns for other reasons so > wouldn't be upset if a size rule had the accidental side-effect > of pushing back on them. I can well imagine the averages for > some WG lists being much larger, especially if editors are > including blocks of existing and proposed text for comment. > But, as a notorious author of long messages and someone who > often prefers consolidated responses to a lot of small messages, > I'd struggle to believe that messages over even a half-megabyte > are frequent or that, when they do occur, we wouldn't be better > off if they were broken into multiple messages (and probably > threads). But all of that is about how we would discuss setting > a size, not whether limits on, or special handling of, messages > of a particular size or "attachment" structure is desirable. > john