How to setup relay in the Plesk for MailEnable for particular IP range?
Configure Server-Wide Mail Settings:
Go to Tools & Settings > Mail Server Settings (in the Mail group). The server-wide mail preferences screen will open on the Settings tab.
There is also an option to allow open relay without authorization, which, by default, is hidden from the user interface.
Opening mail relay without authorization is not recommended because it allows spammers to send unsolicited mail through your server.
If you want to set the open relay, log in to the server's file system, locate the file
root.controls.lock in your Parallels Plesk installation directory (
PRODUCT_ROOT_D/var/root.controls.lock on Unix and
PRODUCT_DATA_D/var/root.controls.lock on Windows platforms) and remove the line
/server/mail.php3:relay_open from this file. The open relay option will show in your control panel.
Note for Windows hosting users: If you do not wish to use relay restrictions for networks that you trust, specify the network IP and mask in the Use no relay restrictions for the following networks: field (e.g.,
22.214.171.124/16) and click the '+' icon. To remove a network from the list, click the '-' icon corresponding to the network you wish to remove.
The relay hosts on the networks in the list are considered not to be potentially operated by spammers, open relays, or open proxies. A trusted host could conceivably relay spam, but will not originate it, and will not forge header data. DNS blacklist checks will never query for hosts on these networks.
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