Outgoing emails sent, resent, or unable to be sent from your Synology MailPlus Server, and incoming emails received or rejected by your Synology MailPlus Server
Real-time server information including high-availability cluster status
Statistics of various kinds of email threats presented by graphs
Statistics of blocked inbound and outbound emails respectively, along with top senders/recipients of such emails
Management
Multiple domain management and configuration settings related to alias, auto BCC, usage limit, and disclaimer in Synology MailPlus Server
SMTP authentication that forces clients to provide user credentials for login while connecting to Synology MailPlus Server via SMTP
SMTP settings and diverse policies for blocking emails that exceed the limits: hostname, SMTP banner, the maximum number of recipients per email, the maximum number of email hops, and the maximum size per email for Synology MailPlus Server
External postmaster, which is set to receive system emails sent to Mailer-daemon and postmaster aliases from other mail servers
Mail delivery settings that allow sending emails through other mail servers so that mail content will not be exposed to the Internet and subject to possible attacks
Synology MailPlus as a relay server that sends emails for servers listed on the trusted list, and receives emails listed on the domain list
Block and allow lists to reject, discard, or accept emails that match the set criteria
Connection policies for blocking emails from unidentifiable domains and hosts that cannot be identified or may cause Synology MailPlus Server to be overloaded
Smooth communication between Synology MailPlus Server and external mail servers/third-party clients via SMTP, POP3, and IMAP
The high-availability structure which maximizes the service uptime during system updates and hardware replacements by switching the mail system to the paired server in seconds
Mailbox quota and the corresponding notification settings for the control of data growth
Mailbox details including sizes and user statuses displayed on the console for easy management
Batch deletion of deactivated users' mailboxes to quickly free up storage space
Mail import and export:
Emails can be imported to a user's mailbox in the SMC or PST format
Users' mailboxes can be exported to PST files
Security
Custom spam filtering rules work with auto-learning to achieve accurate detection
DNSBL filters out spam published through the DNS based on a list of IP addresses of computers or networks
Greylist returns a temporary error to mail clients
Antivirus engines ClamAV and McAfee (paid option) scan all incoming and outgoing emails for viruses. When an email is found infected, the system will delete or quarantine the email and send notifications to the intended recipients
ClamAV antivirus engine databases, such as Google SafeBrowsing database or a third-party database, help detect malicious links in emails
Virus definitions are automatically updated according to the custom schedule
Various authentication mechanisms, including SPF, DKIM, DMARC, and DANE, guard against spam and identity theft
Emails with potentially dangerous elements will be filtered out when scanned by content and attachment file types
MCP (Message Content Protection) rules can filter or block targeted emails. If an email is matched with the rule's criteria, the rule score will be the total sum of the MCP score. If the total MCP score exceeds the MCP threshold score you defined, the mail system will execute the action you have selected from the following: Save to quarantine, Deliver anyway, Delete mail, Notify sender, or Forward
Auditing
Displays logs of the mail queue for users to view the status of emails and to control emails in the queue
Displays logs regarding incoming/outgoing emails from your Synology NAS
Displays administration logs to record setting changes made by administrators
Allows keyword search for deleting or exporting emails
Forwards logs to another server to back them up or transfers logs to a syslog server for centralized management
Tracks the mail system/traffic and sends logs periodically
Mail Migration
Seamless migration tools for Gmail, Google Workspace, Microsoft Exchange, Yahoo, and other IMAP servers
Supports reusing system configurations from Microsoft Exchange for a quick system replacement
Supports migrating emails from Google Workspace (Gmail) per label, with the original structure remaining intact
Multiple tasks for mail migration from external mail servers: custom filters for bypassing spam emails, emails received after a specific date, and emails exceeding the size limit (KB)
Mail migration without asking for access permissions of each source Exchange user account as long as a delegated account is available
Sizing
Recommended number of users: 1,800 at most
Recommended number of emails processed per day: 4,773,000 at most