Hello,

We wish to throttle inbound connections (Delay/Reject) for a domain on SmarterMail 15 Enterprise.

According to https://portal.smartertools.com/kb/a3206/set-up-throttling-for-domains.aspx 

Bandwidth and email throttling allow system administrators to limit the quantity of data that a SmarterMail mail server transmits and/or accepts within a specified period of time.

Even though it mentions Transmits and Accepts, the throttling options are provided only for Outbound mails and Outbound Bandwidth. 

How do we limit Inbound bandwidth / mails on a per user or per domain basis ? 

GSuite/Gmail has something similar which responds with - The user you are trying to contact is receiving mail at a rate that 450-4.2.1 prevents additional messages from being delivered. Please resend your 450-4.2.1 message at a later time. If the user is able to receive mail at that 450-4.2.1 time, your message will be delivered.