[Exim] Limiting received email sizes

Unfortunately, I am at the receiving end of messages from some rather
well-connected senders, ie. people with Really Fat Pipes to the Internet.

These happy chappies think nothing of sending multi-megabyte attachments,
simply because they can.

I know about the message_size_limit, but if I read the Spec right, it will
process messages up to the limit, and then fail them with a 552. If so,
that's less than ideal, because you will already have wasted bandwidth
receiving x amount of data.

I suppose there's no way currently to get the sending MTA to report the
size of the attachment before transmitting it? It should then wait for an
OK before transmission of the attachment.

Would it need an extension to SMTP?

--
Juha
Take off every sig!