Re: Outbox traffic jam?

[Brian Stafford <brian stafford uklinux net>]

On Thu, 28 June 16:12 Karl O . Pinc wrote:
| On 2001.06.28 04:10 Raven wrote:
| > 
| > On 2001.06.28 03:56 Brian Stafford wrote:
| > > This is getting quite frustrating...
| > 
| > Understandable. Would a report of progress help?
| >  
| > libESMTP 0.8.2 has taken care of most of my problems. I still can't
| send
| > out a large ( > 1 Meg ) attachment, though. Thre's lots of modem
| activity
| > in the attempt and the dialog box reads:
| > 	To: 250 <recipient address>
| > 
| > Eventually, the mail gets shuttled off to the outbox. I suspect that
| > there's a timeout problem involved, especially since I'm currently
| on a
| > 56K
| > modem at the moment and we are talking a span of minutes before
| things
| > give
| > up.
| 
| This is AT&T we're talking about as a ISP, yes?  Perhaps they have a
| maximum size limit on mail that you're exceeding.

This was my thought.  libESMTP implements the SIZE extension so that
the client can discover if a message would be rejected *before*
attempting to transfer it.

However I have observed the following behaviours with servers that
do not implement SIZE but nevertheless impose a maximum message
size limit.

In all cases, the message is transferred at great cost to the sender
on the slow dial up line.

DATA command is rejecetd with 5xx status though its not necessarily
obvious that a size limit was exceeded. Client realises transfer
failed but doesn't know why.  User probably trys again, incurring
further cost and subsequent failure.  User blames crappy client.

DATA command succeeds with a 2xx status code.  Message is silently
dropped (Yahoo).  User is baffled.  User blames crappy client.

DATA command succeeds with a 2xx status code.  Message is silently
dropped and non-delivery notification is mailed to sender.  Still
bad but at least the user gets an explanation.

(What is it with the authors of these programs?  In most cases
the servers in question implement other SMTP extensions.  Why
not advertise the fact there is a limit using the SIZE extension?)

Brian