For Plesk on Windows servers, there is no Outgoing mail mode (Send from domain IP addresses, Send from domain IP addresses and use domain names in SMTP greeting, Send from the specified IP addresses) in Tools and Settings > Mail Server Settings.
How to set up default Outbound IP address for MailEnable?
After changing IP address of the domain mails are still sending from the old IP address. How to fix it?
Note: by default, MailEnable uses IPv6 if it is available in the server, therefore it may be required to disable IPv6 manually. To disable it connect to the server via RDP, and modify the Windows registry. Open branch "HKEY_LOCAL_MACHINESOFTWAREMail EnableMail EnableConnectorsSMTP", set parameter "IPv6 Status Value" to value "0. For details check MailEnable forum tread.
Note: assigning individual outbound IP per post office is possible only for Enterprise and Premium editions of MailEnable as a part of the "Improved Smarthosting" feature.
MailEnable has the option to configure which IP Address is used to connect to remote mail servers and send outbound mail. To access this setting follow steps below:
Open Mailenable Administrator by finding MailEnable in the Programs section of the start menu (or Start screen on Windows 2012).
Go to MailEnable Management > Servers > localhost > Services and Connectors . Right-click SMTP and choose Properties.
Switch to Outbound tab and select desired outbound IP address:
By default, the first adapter/interface added to the computer is always used for outbound traffic.
Right-click on SMTP > Stop and then SMTP > Start.