Details

Select this option to use DNS to route outbound mail. If enabled the connector will use DNS to resolve the IP address of the remote SMTP server.

Rationale:

Basic authentication sends credentials across the network in plaintext. DNS routing helps protect connections from tampering or interception by unauthorized users.

Solution

To implement the recommended state, execute the following PowerShell cmdlet:

Set-SendConnector ‘Connection to Contoso.com’ -DNSRoutingEnabled $true

Supportive Information

The following resource is also helpful.

• https://workbench.cisecurity.org/files/1514

This security hardening control applies to the following category of controls within NIST 800-53: System and Communications Protection.This control applies to the following type of system Windows.

References

• 800-53|SC-11

Source

• Tenable.com/audits