> >> I noticed that some emails are sent immediately
> >> (what I prefer), while other are queued (introducing useless delay)
Same here. Exim 4.90 under FreeBSD 6 on a VPS,
root@lena:/root# exim -bP log_selector
log_selector = +smtp_confirmation +queue_time +queue_time_overall +deliver_time -retry_defer +smtp_incomplete_transaction +smtp_no_mail +incoming_interface
root@lena:/root#
First message was rejected by recipient MTA after end of data
(I don't know whether it's relevant):
2017-12-25 06:26:19 +0200 1eTKLB-00025a-NK <= Lena @ lena.kiev.ua H=ip-1c*0.rusano*ka-net.kiev.ua (bedside.lena.kiev.ua) [94.2*4.28.208] I=[212.109.198.40]:5225 P=esmtpsa X=TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256 CV=no A=plain:<redacted> S=1088 id=20171225042614.GA908 @ lena.kiev
2017-12-25 06:26:22 +0200 1eTKLB-00025a-NK ** <redacted> @ yahoo.com R=remote_domains_throttled T=throttled_smtp H=mta6.am0.yahoodns.net [98.137.159.24] I=[212.109.198.40] X=TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128 CV=no: SMTP error from remote mail server after end of data: 554 delivery error: dd Requested mail action aborted - mta4090.mail.ne1.yahoo.com
2017-12-25 06:26:22 +0200 1eTKLG-00025m-MR <= <> R=1eTKLB-00025a-NK U=mailnull P=local S=2535
2017-12-25 06:26:22 +0200 1eTKLB-00025a-NK Completed QT=5s
2017-12-25 06:26:23 +0200 1eTKLG-00025m-MR => lena <Lena @ lena.kiev.ua> R=localuser T=local_delivery QT=0s DT=0s
2017-12-25 06:26:23 +0200 1eTKLG-00025m-MR => |/home/cgi/data/nokia.pl (Lena @ lena.kiev.ua) <Lena @ lena.kiev.ua> R=aliases T=address_pipe QT=0s DT=0s
2017-12-25 06:26:23 +0200 1eTKLG-00025m-MR Completed QT=0s
Second message to the same recipient domain (but another local_part)
was delayed by Exim until the next queue run, I don't understand why:
2017-12-25 06:27:57 +0200 1eTKMn-00027D-BW <= Lena @ lena.kiev.ua H=ip-1*d0.rusan*vka-net.kiev.ua (bedside.lena.kiev.ua) [94.244.28.2*8] I=[212.109.198.40]:5225 P=esmtpsa X=TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256 CV=no A=plain:<redacted> S=1092 id=20171225042754.GB908 @ lena.kiev
2017-12-25 06:34:46 +0200 Start queue run: pid=8699
2017-12-25 06:34:50 +0200 1eTKMn-00027D-BW => lena_kiev @ yahoo.com R=remote_domains_throttled T=throttled_smtp H=mta7.am0.yahoodns.net [67.195.229.59] I=[212.109.198.40] X=TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128 CV=yes C="250 ok dirdel" QT=6m53s DT=3s
2017-12-25 06:34:50 +0200 1eTKMn-00027D-BW Completed QT=6m53s
2017-12-25 06:34:50 +0200 End queue run: pid=8699
In the header of the second (delayed) message received by yahooMail:
Received: from 127.0.0.1 (EHLO lena.kiev.ua) (212.109.198.40)
by mta4181.mail.gq1.yahoo.com with SMTPS; Mon, 25 Dec 2017 04:34:48 +0000
DKIM-Signature: <redacted>
Received: from ip-1*d0.rusa*ovka-net.kiev.ua ([94.2*4.28.208] helo=bedside.lena.kiev.ua)
by lena.kiev.ua with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256)
(Exim 4.90 (FreeBSD))
(envelope-from <Lena @ lena.kiev.ua>)
id 1eTKMn-00027D-BW
for lena_kiev @ yahoo.com; Mon, 25 Dec 2017 06:27:57 +0200
I tried once to reproduce - unsuccessfully
(second message was sent immediately).
In rcpt ACL I use
verify = recipient/defer_ok/callout=10s,defer_ok,use_sender,hold
