What is the difference between the Discard and Reject dispositions?

The correct answer is A. Reject drops the email and informs the sender of the rejection . Proofpoint’s own support guidance distinguishes Discard from Reject by explaining that rejecting a message causes the sender to receive a non-delivery or rejection response, whereas discarding does not provide that SMTP rejection feedback to the sender. In other words, Reject is an explicit refusal communicated back during mail handling, while Discard silently drops the message without notifying the sender in the same way.

This distinction is important in policy design. Administrators may choose Discard when they do not want to generate sender-visible feedback, especially in cases involving spoofed or malicious traffic where a rejection response could be unnecessary or undesirable. They may choose Reject when they want the sending side to receive a clear refusal signal. That is why the other choices are incorrect: Discard is not a temporary resource-based rejection, Reject is not silent, and Discard does not inform the sender of the rejection. In Proofpoint administration, understanding these dispositions helps determine how messages are handled at the SMTP transaction stage and what feedback, if any, is returned to the sender. Based on Proofpoint’s documented behavior, the correct difference is that Reject drops the email and informs the sender of the rejection .