You can quickly oversee the server operation status via a graphical interface:

• Mail Traffic Monitor: Monitors the server's mail traffic by specific time intervals.
• Threat Monitor: Shows the number of email threats blocked by each security setting of your server. You can quickly identify all threat sources and adjust security settings accordingly.
• Server List: Displays a list of server clusters and their operation status.

Mail traffic monitor

The Mail Monitor tab in Server Management displays mail activity statistics over the past. Under the Top List of User Activities section is a list of the most active email addresses of each traffic type.

Monitor traffic by different time interval lengths

You can monitor email traffic in MailPlus Server by hour, day, week, or month. Every data point on the Number of Mails chart represents the total number of emails (of a specific email traffic type) during the time interval. Refer to the steps below to adjust the time interval:

1. Go to Server Management > Mail Monitor.
2. You can select date and time intervals from the Date field and the drop-down menu in the upper-right corner, respectively.

Monitor traffic from a specific time interval

You can use the following two methods to monitor a specific time point:

• Hover the cursor to the left or right end of the chart and click the arrow icons to move forward or backward to a different point of time.
• Select a date from the Date field in the upper-right corner.

Fix the display of detailed data from a specific time

As you hover over different time points, the data displayed in the detailed information panel on the chart will change accordingly. To fix the detailed information panel for a specific time interval, simply move the cursor to the desired interval and left-click on the information panel.

Show or hide data from a certain traffic type

1. Go to Server Management > Mail Monitor.
2. Click Filter under the Number of Mails section and select the checkboxes to show or hide data of certain traffic types.

Export data from a specific time interval

1. Go to Server Management > Mail Monitor.
2. Under the Number of Mails section, click the time interval you want to further investigate on the chart.
3. Click Export on the top.
4. MailPlus Server will export the data as an HTML file.

Threat monitor

The Threat Monitor displays detailed information on email threats and their corresponding sources. You can adjust settings according to threat analysis to protect MailPlus Server.

View general threat analysis

The General Threat Analysis displays threat data and statistics for outbound and inbound emails with a graphical display. Refer to the following steps to adjust the General Threat Analysis settings.

1. Go to Threat Monitor > Overview.
2. Threat data and statistics along with their corresponding settings will be displayed in this section:
   • Time range: Select to show threat statistics over a specific time range.
   • Threat list: See the percentage statistics of each threat type. To see count statistics, hover the mouse over a specific type.
   • Threat doughnut chart: See the percentage statistics of each threat type by selecting or deselecting threat types on the right.
   • Antispam function: See the antispam engine's status. To modify its relevant settings, click to jump to the relevant page.
   • Antivirus function: See the antivirus engine's status. To modify its relevant settings, click to jump to the relevant page.
   • DNSBL Self-check: See if the Synology NAS is on a DNSBL.

View external threat analysis

The external threat analysis displays the sources of blocked inbound emails and the corresponding count statistics.

1. Go to Threat Monitor > Overview.
2. Under the External Threat Analysis section, you can find a threat map and count statistics of each source:
   • Threat map: Each circle on the graph represents a threat source area. As more blocked emails originate from a specific area, its corresponding circle expands. To view the count statistics, simply hover the mouse over a circle.
   • Threat Source: This list shows the top six sources of blocked emails with their corresponding counts.

View blocked inbound and outbound mail

In the Inbound and Outbound sections, you will find statistics for blocked inbound and outbound emails, along with the top senders and recipients of these emails.

1. Go to Threat Monitor.
2. Click the Inbound or Outbound tab.
   • Time range: Select the time range to see the statistics of blocked outbound or inbound emails over a specific period.
   • Blocked Mail Statistics: The chart shows the trends of each threat type of inbound or outbound emails over the selected time range.
   • Top Senders of Blocked Mail: The table shows the top 10 senders of blocked inbound or outbound emails with count statistics.
   • Top Recipients of Blocked Mail: The table shows the top 10 recipients of blocked inbound or outbound emails with count statistics.

Server list

Get a quick overview of MailPlus Server on the Server List tab of the Server Management page, where you can find information on CPU, RAM, and network usage. Below is a list of possible statuses for each MailPlus Server function:

• Running: Running properly
• Stopped: Not enabled
• Abnormal: Not functioning properly due to some issues that need to be resolved
• Not Installed: This only applies to MailPlus when it has not yet been installed.
• Getting ready: You have just enabled or disabled this function, and it is ready to switch the status.
• Syncing mails: When you are setting up or removing a MailPlus high-availability cluster, the system will automatically start syncing emails.

Check settings

Review your MailPlus Server settings and compare them with Synology's suggested settings in the Check Settings section. Additionally, you can observe the effects of each setting here. Refer to the following steps:

1. Go to Server Management > Server List.
2. Click Check Settings.

Check pending emails in the mail queue and determine which action to take.

Monitor messages in the mail queue

On the Queue page, you can review all emails that are currently pending to be sent to other servers or are scheduled for a resend after being rejected. The information about emails in the queue will be presented as follows:

• Date and time when an email entered the queue
• Email sender and recipient
• Why a message is waiting in the mail queue (The Description column shows why an email failed to be delivered.)

Mail queue statuses are categorized into the following three types:

• Hold: Messages are to be processed.
• Active: Messages are now being processed.
• Deferred: Messages failed to be delivered and will be resent later.

Manage messages in the mail queue

You can choose to immediately redeliver or cancel the delivery for messages in the queue. Refer to the following steps to manage messages in the mail queue:

1. Go to Queue to do the following:
   • To redeliver a message, select the message in the mail queue and click Resend. The status of the message will switch from Hold to Active.
   • To remove a message, select the message in the mail queue and click Clear. The message will be removed from the queue.
   • To resend all messages, click Resend All.
   • To remove all messages, click Clear All.
2. You can also search for messages in the search bar in the upper-right corner of the page to view the statuses of the messages.

On the Auditing page, you can:

• View logs: View, search, and analyze the messages recorded in logs.
• Archive and manage logs: Configure various management settings such as archive intervals, rotation rules, and sending logs to the secondary server.
• Enable log report: Receive log reports through email notifications.

Transaction logs

Transaction logs provide information about sent and received emails, as well as related events such as spam detection, message delivery, and error notifications.

To export transaction logs:

Click Export to specify the file type, log count, and which columns to include. You can refine the exported data by applying a search filter or adjusting the sorting of the list.

To view transaction logs:

Select a log entry from the list and click Details to review delivery history and security issues.

To analyze mail traffic:

Click Usage Analysis to get an analysis of the interaction between MailPlus Server and each email address or domain.

Client access logs

Client access logs provide insights into user activities, including connections, email operations, and authentication processes, from the client side.

To export client access logs:

Click Export to specify the file type, log count, and which columns to include. You can refine the exported data by applying a search filter or adjusting the sorting of the list.

To view client access logs:

Select a log entry from the list and click Details to check all the related information, statistics, and events.

Admin logs

Admin logs track setting changes made by administrators.

Select either of the following storage locations from the top menu and then export logs to create a backup in the form of an HTML file:

• Internal database: Logs stored in the system default folder on your Synology NAS
• External database: Logs stored in a custom folder on your Synology NAS

Archive logs

To archive logs:

Configure the archiving settings for MailPlus logs. Logs will be archived in the following formats:

• Transaction logs: CSV files
• Client access logs: CSV files
• Admin logs: SQLite database files
• Postfix logs: TXT files

Refer to the following steps to archive logs:

1. Go to Log Management and select Enable log archiving.
2. Select a shared folder as the Archive destination to store the archived logs.
3. Specify when to run the archive task.

The archive feature will be disabled if you have no access to the shared folder.

To access archived logs:

Click Archived Log to check the database files of admin and Postfix logs from different sources in an email cluster:

• Main log: Logs on the primary server.
• Received log: Logs forwarded from the primary server to the secondary server. You can download admin log files and view them directly on the Admin Log tab by selecting External database from the menu.

Transfer logs to secondary server

Once a high-availability cluster is set up, logs will be collected on the primary server. You can send a copy of transaction logs, client access logs, admin logs, and Postfix logs to the secondary server.

1. Go to Log Management > Log Transfer.
2. Select Transfer logs to the secondary server.
3. Click Apply to save the settings.

Transfer logs to a syslog server

Refer to the following steps to send logs to a syslog server:

1. Go to Log Management > Log Transfer.
2. Select Transfer logs to a syslog server.
3. Enter the information of the syslog server.
4. If you select Enable secure connection (SSL), you might need to click Import Certificate to import the certificate of the syslog server before proceeding.
5. Click Apply to save the settings.

Set up log rotation rules

Rotate logs based on either a set time period or a specific number limit to conserve server space and ensure storage efficiency.

Go to Log Management to configure the following rules:

• For Postfix logs:
  • Log size cannot be larger than (MB): When the log file size reaches the limit you specified, it will be packed up as an .xz file.
  • Log rotation period: Logs will be packed up as an .xz file at the frequency you set. When more than 10 .xz files are archived, the oldest file will be removed to free up some space for the new logs.
• For transaction logs and client access logs:
  • Keep logs for (days): Logs will be automatically deleted after the retention period expires.
  • Limit the number of logs to: Specify the maximum number of logs to retain. Older logs will be rotated as new ones are generated.

Set up daily reports

You can enable the daily report feature to send logs from the previous day to be sent to a specific email address.

Refer to the following steps to set up daily reports.

1. Go to Log Management and select Enable daily report.
2. Specify the delivery time and the recipient's email address.

Set up mail searches

You can find all the indexed emails in MailPlus Server, as well as view, delete, and export search results.

Refer to the following steps to create a mail search task:

1. Go to Mail Search.
2. Click the plus icon (+) to create a new task.
3. Enter a Task name.
4. Set Search Conditions:
   • Pre-defined conditions: You can add multiple search conditions to a search task. Select from the drop-down menu to find emails that match All or Any of the conditions and define those conditions by Sender, Recipient, Subject, Keyword, Mail Size (MB), or Date that includes or excludes the entered keywords.
   • Custom: You can customize search conditions using search operators and keywords. For example, to look for an email about GDPR sent after May 25th, 2018 from the address admin@synology.com, you can enter after:2018/05/25 AND from:admin@synology.com AND GDPR as your search condition.

Search Operator	Usage	Example
from:	Messages from the specified sender	from:amy
to:	Messages sent to the specified recipient	to:david
subject:	Messages with certain words in the subject line	subject:dinner
OR	Messages that match multiple specified terms	from:amy OR from:david
- or NOT	Messages that should be removed from search results	dinner - movie
( )	Messages containing the specified terms grouped together	subject:(dinner movie)
in:	Messages in the specified mailbox. Enter the mailbox name using the following guidelines: Default mailboxes such as Inbox, Draft, and Archived: Use English. Custom mailboxes: Use the language in which you named the mailbox.	in:Inbox in:work
label:	Messages that have a certain label	label:friends
before: or after:	Messages sent during a certain period	after:2004/04/16
larger: or smaller:	Messages larger or smaller than a certain size in MB	larger:10M
filename:	Attachments with a certain name or file type	filename:pdf
has:attachment	Messages with attachments	has:attachment
is:starred	Starred message	is:starred
is:unread	Unread message	is:unread

5. Set Target User. If no target users are specified, the task will search all users by default.
6. Click OK and the search task will start immediately.
7. You can stop a task in progress by selecting the task and clicking Stop tasks on the right panel. Click Search if you want to restart a task.
8. You can Edit, Copy, or Delete a task by selecting it and clicking on the corresponding icon.

View mail search results

1. Go to Mail Search and select a complete search task.
2. On the right panel, you can Download task reports to view the details of a task, including the number of searched emails as well as which emails have been deleted from MailPlus Server.
3. You can also click View Result. In the pop-up window, you can view, delete, or export each email. Details of each email will appear in the right section when you select it. You can also download the original mail or its attachments or open the email in a new tab.

Export mail search results

We recommend that you always export important mail search results and keep them on your local device as backups in case of future needs.

1. Go to Mail Search and select a complete search task.
2. Click View Result on the right panel.
3. Select the emails you wish to export and click Export.
4. You can click the arrow icon next to the Export button to further specify whether to export both the mail list and the original emails or only the mail list.
5. The exported mail list can be found as a file named export_list.csv. Exported original mails can be found as .eml files in the eml folder.

Import mail search results

After exporting search results, you can edit the email list (export_list.csv) with CSV-supported editors to refine the results. Then, you can import the modified list to MailPlus Server for auditing.

1. Go to Mail Search and click the Import tasks icon next to the trash can icon.
2. Upload the export_list.csv file.
3. Click Import.
4. Once the import is complete, the task will appear at the top of the task list.

You can use the SNMP service to monitor key mail server information, including:

• Mail delivery results
• Security events
• Mail queue
• IMAP/POP3/SMTP connections
• Postfix/Dovecot service status

To access this service, go to DSM Control Panel > Terminal & SNMP > SNMP. For detailed information, refer to the SNMP MIB Guide.