On Fri, Jul 12, 2024 at 01:54:38AM +0200, Steffen Nurpmeso wrote:
> |> I have a problem in that I would like several senders to be able
> |> to send larger messages.
> |
> |You may as well advertise the largest supported size, it is better
> |better than advertising just "SIZE", because clients that honour
> |"SIZE=<limit>", but don't send "SIZE=" in mail from will be able to
> |avoid attemting transmission of overly large messages.
>
> But not if the largest size is 500000.
But the *largest* size is NOT 500000, it is the message size that those
"several senders" should be allowed to send. That's the size to
advertise in the smtpd(8) "EHLO" response.
There is NOTHING to be gained by hiding the limit completely and sending
"SIZE" with no limit. You're then just hiding useful information from
the sending client.
> I would assume that if 250-SIZE is reported, a smart(er than mine)
> mail client would take more useful steps in case of 5.* than if
> not.
No client would do better in that case than with "250-SIZE 10000000"
if (10MB is the limit for the "several senders". You can still
(policy service) reject sizes over 500000 for the remaining senders,
for whom even the much larger "10000000" is more useful than no limit.
> Ie, it could give users some feedback that it otherwise
> could (or would) not.
No, there is no scenario in which no limit is better than an explicit
maximum.
> |> Letting aside the "extended MAIL" client command that i never have
> |> seen, what i would hope for would be that postfix simply says
> |>
> |> 250-SIZE
> |
> |There's little to gain by doing that. Instead, just advertise the
> |absolute ceiling.
>
> The problem is that the ceiling is too low.
You're not paying attention, the limit to advertise is the *largest*
message size (not the typical) that you might accept from any source,
to any recipient. Your policy service can then enforce lower limits
for the majority of deliveries.
> But it definitely is the ceiling, except for fewest (once that is
> implemented).
That's a contradiction, it is either the ceiling or it isn't, there's no
"except".
--
Viktor.
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