An engineer has enabled LDAP accept queries on a listener. Malicious actors must be prevented from quickly identifying all valid recipients. What must be done on the Cisco Secure Email Gateway to acco

Bounce Verification is a feature used to prevent backscatter spam by validating that incoming bounce messages are legitimate, not to prevent directory harvesting.

Configuring incoming content filters is used to inspect the content of emails for spam, malware, or policy violations, not to prevent the enumeration of valid email addresses.

Bypassing LDAP access queries in the recipient access table would allow all recipients to be accepted without LDAP lookup, making it easier for attackers to identify valid recipients, thus directly contradicting the goal of preventing directory harvesting.

Directory Harvest Attack (DHA) Prevention on the Cisco Secure Email Gateway is specifically designed to thwart attempts by attackers to guess valid email addresses by sending a large number of invalid recipient addresses and observing the server's responses. This feature protects the directory when LDAP accept queries are enabled by limiting the information provided to potential attackers about valid recipients.