ietf-smtp
[Top] [All Lists]

Re: [ietf-smtp] SMTP Greylisting Retry Hints + PRDR

2019-02-07 11:17:37
Hello Valdis,

imagine a mail with an empty Subject: for two recipients.  The first recipient 
does not want to receive emails without subject, the second recipient has no 
problem with this.

This is what happens at SMTP level:

EHLO xx
250 blah blah
MAIL FROM:<me(_at_)example(_dot_)org>
250 OK
RCPT TO:<one(_at_)example(_dot_)com>
250 Okay
RCPT TO:<two(_at_)example(_dot_)com>
421 Retry soon retry=00:00:00
DATA
Subject:
From: me(_at_)example(_dot_)org
Message-Id: 12a
To: one(_at_)example(_dot_)com, two(_at_)example(_dot_)com
....
.
550  You forgot to fill the Subject!
MAIL FROM:<me(_at_)example(_dot_)org>
250 ok
RCPT TO:<two(_at_)example(_dot_)com>
250 okay
DATA
Subject:
From: me(_at_)example(_dot_)org
Message-Id: 12a
To: one(_at_)example(_dot_)com, two(_at_)example(_dot_)com
....
.
250 accepted

After all, if the server was
willing to accept a retry later on in the same TCP connection, why
didn't it
just go ahead and accept the mail the first time?

Because the server wants to accept the email only for the second recipient.  At 
the moment RCPT is communicated the server does not know yet, if all recipents 
are willing to accept the message.

Regards
  Дилян


On February 7, 2019 5:30:05 PM GMT+01:00, 
valdis(_dot_)kletnieks(_at_)vt(_dot_)edu wrote:
On Thu, 07 Feb 2019 07:19:00 +0000, ���������� ���������������� said:

Retrying the same RCPT TO: before doing DATA/MAIL FROM: will lead to
the same
421/451 reply.  This might be different for grey listing.

Doing RCPT TO: after EHLO/RSET/another MAIL TO will lead to different
results
(accepting after RCPT).

Are we sure that's the semantics we wanted?  After all, if the server
was
willing to accept a retry later on in the same TCP connection, why
didn't it
just go ahead and accept the mail the first time?

_______________________________________________
ietf-smtp mailing list
ietf-smtp(_at_)ietf(_dot_)org
https://www.ietf.org/mailman/listinfo/ietf-smtp