Server-wide Email Settings in Plesk
To view and configure mail setting for the Plesk server Go To Tools & Settings > Mail Server Settings (in the Mail group).
To enable the mail service server wide check on the check-box "Enable mail management function in Plesk".
Installed Mail Server : Mail server Installed will be displayed here.
Installed IMAP/POP3 server : It will display which service is installed for IMAP/POP3 in this server as here "Courier-IMAP is installed" .
Maximum message size : Enter the value for maximum message size you can sent from the server.
Maximum number of connections : Number of concurrent connections users can make to the server via IMAP/POP3 protocol.
Maximum number of connections per IP address : The number of simultaneous connection that can be done from one IP address.
Enable SMTP service on port 587 on all IP addresses : Check the check-box on so to enable port 587 for all the IP addresses as to allow your customer to specify the port 587 for outgoing SMTP connection.
Outgoing mail mode : In Plesk one can configure outgoing mail mode
Relaying is an option which allows mails to be sent from with or without authentication from any one over internet. , it routes an e-mail to the correct destination . There are different types of email routing detail discussion is given below:
Outgoing Emails Limitation.
Switching outgoing limitations will help you out in preventing spam mails to get relayed to other email address, you can configure the limitation as per your server need, there are different types of limitations which can be configure to stop outbound spam.
To activate outgoing email limitation check the check box
Default limit on outgoing messages from a mailbox : The maximum number of mails that a user can send within one hour.
Default limit on outgoing messages from a domain: The maximum number of mails that all user of a domain can send within one hour.
Default limit on outgoing messages from a subscription: The maximum number of mails that all the users of a subscription can send within one hour.
Allow users and scripts to use Sendmail: Enabling the option subscription system users and scripts can send mails from the server, the maximum number of mails that can be sent depend upon the number allowed in the subscription.
Show reports based on statistics for the last: Reports are generated against the user or subscription system users those who exceeds the outgoing limit.
Send an email notification every: Send notification on hourly basis to server admin with the details of users who has exceeded the hourly outgoing limits.