Re: [exim] time skew: SMTP delay

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Author: Felipe Gasper
Date:  
To: Jeremy Harris
CC: exim-users
Subject: Re: [exim] time skew: SMTP delay


> On Mar 30, 2021, at 10:33 AM, Jeremy Harris via Exim-users <exim-users@???> wrote:
>
> On 30/03/2021 15:02, Felipe Gasper via Exim-users wrote:
>>     I’m noticing if I have a server time-skewed into the future, and I send a message to Exim on that server, the SMTP client never receives confirmation of receipt of the message.
>>     This causes that client to think the message send failed, though Exim does actually enqueue the message for remote delivery. Thus, the client resends the message, which causes the recipient to receive multiple copies of the message.
>>     strace is showing:
>> -----
>> [pid 25596] write(4</var/log/exim_mainlog>, "2021-03-30 10:55:28 1lRGiG-0006eq-QA <= canada@??? H=(felipes-mbp.lan) [10.3.4.84]:49684 P=esmtpsa X=TLS1.2:ECDHE-RSA-AES128-GCM-SHA256:128 CV=no A=dovecot_plain:mailer S=381 T=\"Test sent from ./smtp_send_test.pl\" for felipe@???\n", 254) = 254
>> [pid 25596] rt_sigprocmask(SIG_BLOCK, [ALRM], [], 8) = 0
>> [pid 25596] setitimer(ITIMER_REAL, {it_interval={tv_sec=0, tv_usec=0}, it_value={tv_sec=7198, tv_usec=625000}}, NULL) = 0
>> [pid 25596] rt_sigsuspend(~[ALRM RTMIN RT_1], 8
>> -----
>>     … and there it hangs. The socket never closes, so the client eventually times out the connection.
>>     Has anyone else encountered something of the like? Notwithstanding that clock-skews of 2 hours are their own problem, could Exim maybe handle this a bit more gracefully?

>
>
> What Exim version? What platform?
>
> Behaviour changed in 4.94, for platforms with _POSIX_MONOTONIC_CLOCK.


Exim 4.94
CentOS 7, default kernel (3.10.0-1160.11.1.el7.x86_64)

Incidentally, I’m setting system clock via `date`.

Thank you!

-FG