On Fri, Jul 07, 2023 at 11:54:44AM -0400, Viktor Dukhovni via Postfix-users
wrote:
If the client uses PIPELINING, the pipelined "RCPT TO" after the rejected
"MAIL FROM" will presumably be logged.
On 7/7/2023 11:07 AM, Viktor Dukhovni via Postfix-users wrote:
Turns out that's not the case. Postfix does not log client "syntax"
errors and sending "RCPT TO" once "MAIL FROM" is rejected "RCPT TO"
is a "50x" syntax error:
MAIL FROM:<...> SIZE=1234567890
552 5.3.4 Message size exceeds fixed limit
RCPT TO:<...>
503 5.5.1 Error: need MAIL command
Logs:
Jul 7 12:00:36 amnesiac postfix/smtpd[5728]:
connect from localhost[127.0.0.1]
Jul 7 12:00:58 amnesiac postfix/smtpd[5728]:
NOQUEUE: reject: MAIL from localhost[127.0.0.1]:
552 5.3.4 Message size exceeds fixed limit; ...
Jul 7 12:01:13 amnesiac postfix/smtpd[5728]:
disconnect from localhost[127.0.0.1]
ehlo=1 mail=0/1 rcpt=0/1 quit=1 commands=2/4
On 07.07.23 11:58, Noel Jones via Postfix-users wrote:
It gets worse...
Some client will see the 250-SIZE XXXXX in the EHLO response, and give
up immediately, without ever sending a MAIL FROM that it knows will
fail. All postfix is able to log is a connect, quickly followed by a
disconnect. This is not really postfix's fault, but it's near
impossible to debug from the postfix side.
Blame SMTP.
I guess The point was to reject mail ASAP, avoiding useless delays (e.g when
listing tens or hundreds of recipients) and useless checks (when validating
tens or hundreds of recipients).
Hypotetically, server could accept/validate recipients just to reject the
DATA command with EFBIG message, but that would require patching postfix and
the measures above (not send and ignore SIZE).
You could probably use a milter, or a policy_service that rejects
based on size. Set the main.cf size value to something big, and reject
after the client sends all the data. This is inefficient, but would
work.
Very inefficient - would need to receive all huge e-mail just to say it
can't accept it. Depending on size, you could run out of space on mail spool
partitions (risky).
--
Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
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