Re: [Exim] Any benefits to having exim use the SIZE command?

> True, no spam I've seen was big enough to be considered "too big". I guess
> a more relevant issue would be clueless users who think that sending their
> 10mb adobe acrobat brochure via email is a smart thing to do, and all those
> amateur artists who just *have* to send their 50mb high res picture to a
> client via email! *smack smack smack*

I have set the limit at work to 12mb in and 12mb out (in being smtp receive
and out being local delivery to mail boxes) Occasionally, someone has a
bunch of files (say drawings or pictures of equptment) that totals say 15mb
after expansion. I lift it long enough for them to go through. The upper
limit (default) is 50m. I check this at MAIL, RCPT and DATA times as well
as have a router per user to block sizes (No size= on mail from line and
can't check recipients after data). Works rather well.

I personally wish SMTP could be LMTP (globally) I see more benefit in
something like this than smtp (LMTP sends a code for each rcpt after data)

> I don't know if any MTAs actually use the SIZE command as an accurate count
> for message size, however exim does apparently use it to check disk space:
>
> "The amount of disk space available is checked whenever SIZE is received on
> a MAIL command, independently of whether message_size_limit or
> check_spool_space is configured, unless smtp_check_spool_space is set false.
> A temporary error is given if there is not enough space. If
> check_spool_space is set, the check is for that amount of space plus the
> value given with SIZE, that is, it checks that the addition of the incoming
> message will not reduce the space below the threshold."

Forgot about that.

> I don't know if that could cause any problems, but I guess there is a chance
> if you're critically low on spool space, and someone misrepresents the
> actual message size to be much smaller than the message really is once sent
> across in the DATA stage. No idea if SIZE is also used elsewhere, and/or if
> other mail servers use it at all (I thought I read somewhere that exim will
> reject a message if it sends more data than reported with the SIZE command -
> no idea where I thought I saw that though).

I thought about having my primary (on dialup) to block messages over say 50k
or so and let them fall over to my backup. Unfortunately, damage is done
after data so it won't matter then. My secondary will local drop email for
the primary and forward to primary. I did this so I could get my mail here
if the primary is down (you know how dialups are) =)

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