Re: Abort data transfer?

Thanks to all who answered this question.

Hector Santos wrote:
> SM wrote:
> > Hi David,
> > At 14:29 17-10-2009, David MacQuigg wrote:
> > > Is it permissible to abort data transfer before the end of data, say 
> > > after you have received all headers, and you know the DKIM sig is bad?
> > > RFC-5321 section 3.3 says:
> > >
> > >   If the verb is initially accepted and the 354 reply issued, the DATA
> > >   command should fail only if the mail transaction was incomplete (for
> > >   example, no recipients), if resources were unavailable (including, of
> > >   course, the server unexpectedly becoming unavailable), or if the
> > >   server determines that the message should be rejected for policy or
> > >   other reasons.
> > That paragraph is about the DATA command.  You haven't received any 
> > headers yet.  You don't know whether the DKIM signature is bad.  This 
> > is more of a SMTP question though.  You can do anything you wish for 
> > policy reasons.  As long as you adhere to the RFC 5321, you won't 
> > cause interoperability or hard to debug problems.  I suggest not 
> > aborting the data transfer to avoid such problems.
> +1. Aborted Data transfers can cause retransmissions. Unfortunately, 
> it is better to receive the entire payload and then issue a negative 
> response.
Forget about DKIM.  What if there is some other reason to abort, like 
the payload is too large?  We cannot just continue receiving data 
forever.  Is there a "permissible" way within SMTP to abort during data, 
or should I just ignore these ambiguous requirements, and either: 1) 
Send a TCP reset, or 2) Let the transmitter hang.
-- Dave