What best describes the Auto Allow Setting - Strict in Mimecast?

The Auto Allow Setting - Strict in Mimecast is designed to manage and control the flow of emails with a focus on allowing specific trusted senders while still maintaining some level of security through checks. It specifically bypasses spam checks for external senders to internal recipients, which means that emails from those selected external sources will be allowed to bypass standard spam filtering processes.

This setting is used when an organization wants to ensure that important communications from trusted external parties are delivered, without the risk of being caught up in spam filters, which could delay or block vital information. By utilizing this approach, Mimecast provides an efficient way of managing trusted communications while still requiring that other emails undergo the normal scrutiny of spam checks. This leads to a more streamlined communication process for internal users while balancing the need for security against spam threats.

The other choices do not accurately encapsulate the function of the Auto Allow Setting - Strict. For instance, blocking all external communications would negate the purpose of allowing trusted emails, and allowing all emails with no checks would introduce significant risk. Additionally, stating that it is enforced on all email traffic misrepresents its selective nature aimed at specific external senders.