Re: [exim] Exim 4.88: LMTP over TCP timeouts

Am 2017-03-07 um 11:02 schrieb Jeremy Harris:
> On 07/03/17 09:28, Peter Rindfuss wrote:
>> We are using Exim 4.88 on Debian with a non-Debian config. We deliver to
>> our mailboxes on a separate Dovecot IMAP machine using LMTP over TCP
>> (SMTP transport). A few times a day we see "Connection timed out" on the
>> transport. It strikes me as odd that the time between the reception of a
>> message and the delivery timeout is typically around 20 seconds, whereas
>> all timeout values are at their defaults, which is 5 minutes for
>> connect, command and data. Any ideas on this?
>
> A shorter system-level timeout may be being applied, firing before
> the Exim one. Have a look around /proc/sys/net/ipv4 for values
> such as "tcp_syn_retries".
>

Jeremy, thank you.

/proc/sys/net/ipv4/tcp_syn_retries accounts for the observed timeout,
indeed. I increased it from 3 to 5. Unfortunately, I got spurious
timeouts again, this time after 60s instead of 20s.

We had just moved Exim to a new server. On the old server with an older
Suse Linux and Exim 4.75 and the same target host, we never saw any such
timeout with tcp_syn_retries = 5.

Peter