Glenn Anderson wrote:
At 5:10 pm -0400 30/5/2011, Hector Santos wrote:
So basically, on the first DATA attempt our data filter returned a
FAIL=451 which was a greylist filter script, the transaction and state
was cleared with RSET. Then during the 2nd attempt the client was able
to get by the initial rejection.
If you read a bit further in to section 4.1.1.5 it says:
It is
effectively equivalent to a NOOP (i.e., it has no effect) if issued
immediately after EHLO, before EHLO is issued in the session, after
an end of data indicator has been sent and acknowledged, or
immediately before a QUIT.
If your server is adhering to the standard, you would still have the
same problem even if the spammer left out the RSET, or replaced it with
a NOOP, so this isn't a problem with RSET.
Glenn.
Hi Glenn,
Hmmm, the NOOP is truly a "NO OPeration" command which is a carry on
from the FTP model (which SMTP is based on). Its an old school "keep
alive" concept to avoid idle timeouts.
I would not interpret RSET as not an "NO OPeration" concept - it will
literally reset, delete, purge, etc, stuff already temporarily
recorded by the server for the current session pending a QUIT or MAIL
command to activate the the final acceptance (per spec) for the mail
delivery. Not I said per spec, because there are systems that will
put the mail in delivery motion once that final DATA <CRLF>.<CRLF> is
received and prior to an pending client command.
Is this wrong?
--
Sincerely
Hector Santos
http://www.santronics.com