Hello and thank you for your comment.
Yes I have modified postfix main.cf by hand when I implemented openDKIM and dk-filter. I know I may have to redo after a Zimbra upgrade.
To fill you in a bit more posix / samba is also implemented. I have gone away from CentOS 5 old Samba 3.0.33 packages and installed Enterprise Sernet samba v3.5. And a CaCert certificate.
That is all on top of my standard Zimbra installation if memory serves me right.
Mid February I upgraded to from Zimbra v5 to v6. I checked the log and this error did happen way before that too.
Here my master.cf (master.cf.in)
at the bottom I added no_milters to the following line
-o receive_override_options=no_header_body_checks,no_ unknown_recipient_checks,no_address_mappings,no_mi lters
Here my main.cf
Note: Changed those two entries to hide real names
myhostname = mail.example.com
relayhost = mail.myisp.net:25
Entries added by hand at the bottom:
smtpd_milters = inet:localhost:8891 inet:localhost:8892
non_smtpd_milters = inet:localhost:8891 inet:localhost:8892
milter_default_action = accept
Code:
sender_canonical_maps = proxy:ldap:/opt/zimbra/conf/ldap-scm.cf
virtual_alias_domains = proxy:ldap:/opt/zimbra/conf/ldap-vad.cf
lmtp_connection_cache_time_limit = 4s
recipient_delimiter =
smtpd_tls_cert_file = /opt/zimbra/conf/smtpd.crt
smtpd_tls_auth_only = yes
myhostname = mail.example.com
virtual_mailbox_domains = proxy:ldap:/opt/zimbra/conf/ldap-vmd.cf
mydestination = localhost
mailbox_size_limit = 0
setgid_group = postdrop
smtpd_client_restrictions = reject_unauth_pipelining
queue_run_delay = 300s
minimal_backoff_time = 300s
virtual_alias_maps = proxy:ldap:/opt/zimbra/conf/ldap-vam.cf
transport_maps = proxy:ldap:/opt/zimbra/conf/ldap-transport.cf
message_size_limit = 1024000000
sendmail_path = /opt/zimbra/postfix/sbin/sendmail
broken_sasl_auth_clients = yes
lmtp_connection_cache_destinations =
alias_maps = hash:/etc/aliases
manpage_directory = /opt/zimbra/postfix/man
policy_time_limit = 3600
smtpd_helo_required = yes
in_flow_delay = 1s
daemon_directory = /opt/zimbra/postfix/libexec
maximal_backoff_time = 4000s
virtual_transport = error
mynetworks = 10.1.1.0/24 127.0.0.0/8
bounce_queue_lifetime = 5d
smtpd_recipient_restrictions = reject_non_fqdn_recipient, permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination, reject_unlisted_recipient, reject_invalid_hostname, reject_non_fqdn_sender, permit
lmtp_host_lookup = dns
smtpd_tls_loglevel = 1
relayhost = mail.myisp.net:25
disable_dns_lookups = no
smtpd_sasl_authenticated_header = no
mail_owner = postfix
virtual_mailbox_maps = proxy:ldap:/opt/zimbra/conf/ldap-vmm.cf
content_filter = smtp-amavis:[127.0.0.1]:10024
smtpd_tls_security_level = may
mailq_path = /opt/zimbra/postfix/sbin/mailq
header_checks =
queue_directory = /opt/zimbra/data/postfix/spool
newaliases_path = /opt/zimbra/postfix/sbin/newaliases
smtpd_data_restrictions = reject_unauth_pipelining
local_header_rewrite_clients = permit_mynetworks,permit_sasl_authenticated
smtpd_reject_unlisted_recipient = yes
propagate_unmatched_extensions = canonical
command_directory = /opt/zimbra/postfix/sbin
smtpd_tls_key_file = /opt/zimbra/conf/smtpd.key
smtpd_sasl_auth_enable = yes
smtpd_milters = inet:localhost:8891 inet:localhost:8892
non_smtpd_milters = inet:localhost:8891 inet:localhost:8892
milter_default_action = accept
Just to show the frequency of the error:
Mar 18 07:02:49 tracker slapd[12782]: SASL [conn=5805] Failure: realm changed: authentication aborted
Mar 18 07:17:50 tracker slapd[12782]: SASL [conn=6036] Failure: realm changed: authentication aborted
Mar 18 07:32:50 tracker slapd[12782]: SASL [conn=6226] Failure: realm changed: authentication aborted
Mar 18 07:47:51 tracker slapd[12782]: SASL [conn=6446] Failure: realm changed: authentication aborted
Mar 18 08:02:51 tracker slapd[12782]: SASL [conn=6769] Failure: realm changed: authentication aborted
Mar 18 08:17:52 tracker slapd[12782]: SASL [conn=7000] Failure: realm changed: authentication aborted
Mar 18 08:32:52 tracker slapd[12782]: SASL [conn=7222] Failure: realm changed: authentication aborted
Mar 18 08:47:52 tracker slapd[12782]: SASL [conn=7497] Failure: realm changed: authentication aborted
Mar 18 09:02:52 tracker slapd[12782]: SASL [conn=7679] Failure: realm changed: authentication aborted
Mar 18 09:17:53 tracker slapd[12782]: SASL [conn=7881] Failure: realm changed: authentication aborted
Mar 18 09:32:53 tracker slapd[12782]: SASL [conn=8304] Failure: realm changed: authentication aborted
Mar 18 09:47:53 tracker slapd[12782]: SASL [conn=8463] Failure: realm changed: authentication aborted
Mar 18 10:02:54 tracker slapd[12782]: SASL [conn=8622] Failure: realm changed: authentication aborted
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Source
slapd error in zimbra.log 
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