Message Delivery

Deep Discovery Email Inspector maintains a routing table based on domains and email addresses. Deep Discovery Email Inspector uses this routing table to route email messages (with matching recipient domains or email addresses) to specified destination servers or to destination servers that match specified mail exchanger records (MX records).

There are two message delivery methods:

  • Look up MX record

    When delivering an email message using MX record lookup, Deep Discovery Email Inspector queries the specified MX record, and then delivers the email message to the destination server identified by the MX record.

  • Specify servers

    When delivering an email message using specified servers, Deep Discovery Email Inspector first sends the email message to the destination server with the highest priority. If the server is unavailable, Deep Discovery Email Inspector chooses the remaining servers in descending order of their priority. If multiple destination servers have the same priority, Deep Discovery Email Inspector randomly selects a server for message delivery.

Email messages destined to unspecified domains and email addresses are routed based on the records in the Domain Name Server (DNS). For example, if the delivery domain includes "" and the associated SMTP server is on port 25, then all email messages sent to "" deliver to the SMTP server at using port 25.