Comment 2 for bug 1727699

Hi,

thanks for the investigation, I can give you some other details:

I made a system update with a lot of packages, including this one:
postfix:amd64 3.1.0-3 => 3.1.0-3ubuntu0.1
which I presumed is the cause the problem.

Looking at the package diff I cannot see where the problem is

http://launchpadlibrarian.net/332320988/postfix_3.1.0-3_3.1.0-3ubuntu0.1.diff.gz

but I can tell you that update has changed the file main.cf in this way:

 Index: etc/postfix/master.cf
===================================================================
--- etc/postfix/master.cf (revision 3249)
+++ etc/postfix/master.cf (working copy)
@@ -14,11 +14,6 @@
 #tlsproxy unix - - - - 0 tlsproxy

 # 3 feb 2017: open port 587
-submission inet n - - - - smtpd
- -o syslog_name=postfix/submission
- -o smtpd_tls_security_level=encrypt
- -o smtpd_sasl_auth_enable=yes
- -o smtpd_client_restrictions=permit_sasl_authenticated,reject
 # -o milter_macro_daemon_name=ORIGINATING
 #smtps inet n - - - - smtpd
 # -o syslog_name=postfix/smtps
@@ -27,6 +22,11 @@
 # -o smtpd_client_restrictions=permit_sasl_authenticated,reject
 # -o milter_macro_daemon_name=ORIGINATING
 #628 inet n - - - - qmqpd
+submission inet n - y - - smtpd
+ -o syslog_name=postfix/submission
+ -o smtpd_tls_security_level=encrypt
+ -o smtpd_sasl_auth_enable=yes
+ -o smtpd_client_restrictions=permit_sasl_authenticated,reject
 smtp inet n - y - 10 smtpd
 pickup fifo n - y 60 1 pickup
 cleanup unix n - y - 0 cleanup

(Yes, I have the whole /etc saved in svn on a second machine,
each night the second machine rsyncs its '/etc working copy' from the main server,
then cron sends me an email with the svn diff)

the problem is that with that 'y' the server rejects some email,
reverting it to '-' all is fine as it was before that update
(I mean, the "submission inet" line was not commented before the update)

this is the full list of the updated packages in that day,
maybe some other package was involved?

 --------------------- dpkg status changes Begin ------------------------

 Upgraded:
    apache2-bin:amd64 2.4.18-2ubuntu3.4 => 2.4.18-2ubuntu3.5
    apache2-data:all 2.4.18-2ubuntu3.4 => 2.4.18-2ubuntu3.5
    apache2-utils:amd64 2.4.18-2ubuntu3.4 => 2.4.18-2ubuntu3.5
    apache2:amd64 2.4.18-2ubuntu3.4 => 2.4.18-2ubuntu3.5
    bind9-host:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    binutils:amd64 2.26.1-1ubuntu1~16.04.4 => 2.26.1-1ubuntu1~16.04.5
    ca-certificates:all 20160104ubuntu1 => 20170717~16.04.1
    cpp-5:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    cryptsetup-bin:amd64 2:1.6.6-5ubuntu2 => 2:1.6.6-5ubuntu2.1
    cryptsetup:amd64 2:1.6.6-5ubuntu2 => 2:1.6.6-5ubuntu2.1
    curl:amd64 7.47.0-1ubuntu2.2 => 7.47.0-1ubuntu2.4
    dnsutils:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    g++-5:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    gcc-5-base:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    gcc-5:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    initramfs-tools-bin:amd64 0.122ubuntu8.8 => 0.122ubuntu8.9
    initramfs-tools-core:all 0.122ubuntu8.8 => 0.122ubuntu8.9
    initramfs-tools:all 0.122ubuntu8.8 => 0.122ubuntu8.9
    libasan2:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libatomic1:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libbind9-140:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    libcc1-0:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libcilkrts5:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libcryptsetup4:amd64 2:1.6.6-5ubuntu2 => 2:1.6.6-5ubuntu2.1
    libcurl3-gnutls:amd64 7.47.0-1ubuntu2.2 => 7.47.0-1ubuntu2.4
    libcurl3:amd64 7.47.0-1ubuntu2.2 => 7.47.0-1ubuntu2.4
    libdns-export162:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    libdns162:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    libgcc-5-dev:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libgl1-mesa-dri:amd64 17.0.7-0ubuntu0.16.04.1 => 17.0.7-0ubuntu0.16.04.2
    libgl1-mesa-glx:amd64 17.0.7-0ubuntu0.16.04.1 => 17.0.7-0ubuntu0.16.04.2
    libglapi-mesa:amd64 17.0.7-0ubuntu0.16.04.1 => 17.0.7-0ubuntu0.16.04.2
    libgomp1:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libicu55:amd64 55.1-7ubuntu0.2 => 55.1-7ubuntu0.3
    libidn11:amd64 1.32-3ubuntu1.1 => 1.32-3ubuntu1.2
    libisc-export160:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    libisc160:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    libisccc140:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    libisccfg140:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    libitm1:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    liblsan0:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    liblwres141:amd64 1:9.10.3.dfsg.P4-8ubuntu1.7 => 1:9.10.3.dfsg.P4-8ubuntu1.8
    libmpx0:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libmysqlclient20:amd64 5.7.19-0ubuntu0.16.04.1 => 5.7.20-0ubuntu0.16.04.1
    libnss3-1d:amd64 2:3.28.4-0ubuntu0.16.04.2 => 2:3.28.4-0ubuntu0.16.04.3
    libnss3-nssdb:all 2:3.28.4-0ubuntu0.16.04.2 => 2:3.28.4-0ubuntu0.16.04.3
    libnss3:amd64 2:3.28.4-0ubuntu0.16.04.2 => 2:3.28.4-0ubuntu0.16.04.3
    libpam-systemd:amd64 229-4ubuntu19 => 229-4ubuntu20
    libplymouth4:amd64 0.9.2-3ubuntu13.1 => 0.9.2-3ubuntu13.2
    libpython3.5-minimal:amd64 3.5.2-2ubuntu0~16.04.1 => 3.5.2-2ubuntu0~16.04.3
    libpython3.5-stdlib:amd64 3.5.2-2ubuntu0~16.04.1 => 3.5.2-2ubuntu0~16.04.3
    libpython3.5:amd64 3.5.2-2ubuntu0~16.04.1 => 3.5.2-2ubuntu0~16.04.3
    libquadmath0:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libstdc++-5-dev:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libstdc++6:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libsystemd0:amd64 229-4ubuntu19 => 229-4ubuntu20
    libtsan0:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libubsan0:amd64 5.4.0-6ubuntu1~16.04.4 => 5.4.0-6ubuntu1~16.04.5
    libudev1:amd64 229-4ubuntu19 => 229-4ubuntu20
    libxml2:amd64 2.9.3+dfsg1-1ubuntu0.2 => 2.9.3+dfsg1-1ubuntu0.3
    linux-libc-dev:amd64 4.4.0-93.116 => 4.4.0-97.120
    mysql-client-5.7:amd64 5.7.19-0ubuntu0.16.04.1 => 5.7.20-0ubuntu0.16.04.1
    mysql-client-core-5.7:amd64 5.7.19-0ubuntu0.16.04.1 => 5.7.20-0ubuntu0.16.04.1
    mysql-client:all 5.7.19-0ubuntu0.16.04.1 => 5.7.20-0ubuntu0.16.04.1
    mysql-common:all 5.7.19-0ubuntu0.16.04.1 => 5.7.20-0ubuntu0.16.04.1
    mysql-server-5.7:amd64 5.7.19-0ubuntu0.16.04.1 => 5.7.20-0ubuntu0.16.04.1
    mysql-server-core-5.7:amd64 5.7.19-0ubuntu0.16.04.1 => 5.7.20-0ubuntu0.16.04.1
    mysql-server:all 5.7.19-0ubuntu0.16.04.1 => 5.7.20-0ubuntu0.16.04.1
    ntp:amd64 1:4.2.8p4+dfsg-3ubuntu5.6 => 1:4.2.8p4+dfsg-3ubuntu5.7
    ntpdate:amd64 1:4.2.8p4+dfsg-3ubuntu5.6 => 1:4.2.8p4+dfsg-3ubuntu5.7
    plymouth-theme-ubuntu-text:amd64 0.9.2-3ubuntu13.1 => 0.9.2-3ubuntu13.2
    plymouth:amd64 0.9.2-3ubuntu13.1 => 0.9.2-3ubuntu13.2
    postfix:amd64 3.1.0-3 => 3.1.0-3ubuntu0.1
    python3.5-minimal:amd64 3.5.2-2ubuntu0~16.04.1 => 3.5.2-2ubuntu0~16.04.3
    python3.5:amd64 3.5.2-2ubuntu0~16.04.1 => 3.5.2-2ubuntu0~16.04.3
    systemd-sysv:amd64 229-4ubuntu19 => 229-4ubuntu20
    systemd:amd64 229-4ubuntu19 => 229-4ubuntu20
    udev:amd64 229-4ubuntu19 => 229-4ubuntu20
    unattended-upgrades:all 0.90ubuntu0.7 => 0.90ubuntu0.8
    wpasupplicant:amd64 2.4-0ubuntu6 => 2.4-0ubuntu6.2