Which SMTP proxy action setting is configured for outgoing SMTP traffic?

The focus of this question is on understanding SMTP proxy action settings and their configuration for outgoing SMTP traffic.

The correct answer involves preventing unwanted actions related to outgoing email. The option that is specifically geared toward managing how outgoing SMTP traffic is handled is focused on denying outgoing mail from a particular domain. This action is essential for maintaining control over email communications and preventing the sending of potentially harmful or unauthorized messages from within your network, especially if the domain has been flagged for issues such as spam or malware distribution.

In contrast, other options relate to actions that either manage incoming mail or make modifications to email headers, which aren't directly related to the control of outgoing SMTP traffic. Configuring the proxy to rewrite headers or deny incoming mail would not impact how outgoing mail is processed, which is the central concern of this question. Therefore, focusing on the ability to deny outgoing mail accurately reflects the action setting intended for managing outgoing SMTP traffic.