MTA Role#
This section provides details about the Carbonio MTA’s mail queues, how to interact with them, and how to extract relevant information.
Mail Queue Management#
There are cases in which messages that users send remain stuck in the outgoing queue and can not be delivered to the recipient. When this happens, you can check the MTA queue in different ways:
by executing some commands from CLI
from the Carbonio Admin Panel (see Section Queue)
by using Prometheus/Grafana based dashboards, on which suitable alarms can be defined
CLI commands available#
The following is a list of commands that can be used from the CLI. you can check their manpage for their use and configuration.
postconf
is a Postfix command to view or modify the Postfix configurationpostfix
is the main Postfix command, used to start, stop, and reload the service; flush the queues; check and upgrade the configurationqshape
allows to examine Postfix queues in relation to time and sender’s or recipient’s domainspostqueue
is used to manage queuespostsuper
allows to delete messages from queues (must be run as root)postcat
allows to read messages in queues (must be run as root)
# /opt/zextras/postfix/sbin/postqueue -p|grep someString | awk \
'{print $1}' | /opt/zextras/postfix/sbin/postsuper -d -
This command filters from the queue all messages containing
someString
, then prints only the first field, which is the
e-mail ID and passes to postsuper
, which deletes the messag to
the queue.
Daily E-Mail Reports#
If the MTA logs are concentrated on a single Carbonio Node by
specifying a value for options zimbraLogHostname
, it will be
possible to define an entry in crontab
that sends a daily report;
for example, the following entry in crontab will generate a report
every day at 11:30 PM:
30 23 * * * /opt/zextras/libexec/zmdailyreport -m
The report will contain a lot of useful information, including:
comprehensive statistics about the processed messages: received, delivered, forwarded, deferred, bounced, and so on
Host/Domain summary: message delivery (top 50)
Host/Domain summary: messages received (top 50)
Top 50 senders by message count
Top 50 recipients by message count
Top 50 senders by message size
Top 50 recipients by message size
Details about message deferral, bounce, andreject
Message tracking#
Carbonio makes available the zmmsgtrace
utility: it allows to
track the flow of messages, rebuilding it from the log files.
Useful options are:
--id "msgid" The e-mail ID of the message
--senders "john.smith\@example.com" Rebuild the flow of all messages
sent by john.smith\@example.com
--recipient "john.smith\@example.com" Rebuild the flow of all messages
received by john.smith\@example.com
All these options accept a regexp as value.
A more detailed help is provided by command
$zextras /opt/zextras/libexec/zmmsgtrace --help