[AusNOG] Current "Best Practice" WRT email size

[Ross Wheeler]

On Thu, 26 Nov 2015, David Hughes wrote:

> Please pull it back to something with operational relevance.

Not sure if this is "operationally relevant" or not, I hope so...
I've spent several hours over the last few days trying to find some 
"authorative", current, relevant guide as to what is considered "best 
current practice" guidelines for email attachment sizes.

I know email is being constantly asked to take ongoing abuse and to become 
the defacto file-transport-and-archive system of choice, particularly by 
the technically incompetent, but how far does it go?

Case in point: earlier this week, I had a call from a customer "needing" 
me to increase our mail size. (I thought we were 'reasonably generous' in 
current global terms, at 16MB per message). I asked what he considered it 
needed to be, his response was that "right now" he needs 50-60MB, but that 
he thought it shouldn't have any limit - but if it had to, that 300-500MB 
per message would "probably do for now".

Of course, he doesn't care about any operational issues, about the fact 
that even if I did increase my server to that size, "most of the rest of 
the world" wouldn't accept his mail and it'd bounce back anyway. Turns 
out, he's "mostly" expecting to receive these files... and the 
"undeliverable" mail he was complaining about didn't even leave the other 
parties ISP! (Try explaining THAT to someone who doesn't want to know!)

Lots of places still seem to have a 10MB limit, some smaller, some 
greater, but generally still in the low-tens-of-megabytes range.

Would love to find a reference - partly to keep myself up to date with 
what everyone else is doing, and partly to be able to point this guy to so 
it's not just "Ross saying no".

Thanks,
R.