Trend Micro Email reputation technology is a Domain Name Service
(DNS) query-based service. The following process takes place after IMSVA receives a connection
request from a sending mail server:
IMSVA records
the IP address of the computer requesting the connection.
IMSVA forwards
the IP address to the Trend Micro Email reputation DNS servers and
queries the Reputation Database. If the IP address had already been
reported as a source of spam, a record of the address will already
exist in the database at the time of the query.
If a record exists, Email reputation instructs IMSVA to
permanently or temporarily block the connection request. The decision
to block the request depends on the type of spam source, its history,
current activity level, and other observed parameters.
The figure below illustrates how Email reputation works.