The next step is to configure your MTA to perform the appropriate DNS queries for the type of Email Reputation Services to which you subscribed:
Standard: Reject connections with a 550 level error code (“connection refused”).Your MTA returns this error code to the server initiating the connection because the IP address is in the Standard Reputation database as a known spammer.
Advanced: After querying the standard and dynamic reputation databases, your MTA returns a temporarily deny connection 450 level error code (“server temporarily unavailable, please retry”) if the IP address is in the dynamic reputation database.
Legitimate email servers that may have compromised hosts that are temporarily sending spam may be listed in the dynamic reputation database. If the connection request is from a legitimate email server, it will requeue and try sending the message later. This process will cause a short delay in mail delivery until the listing expires but will not permanently block the email.
Some servers may have additional options for handling questionable IP connections. These options include throttling or routing messages for more detailed scanning.
For detailed configuration and set-up options, refer to your product manuals and/or technical support organization. You can also refer to: https://success.trendmicro.com/