What aspect of email is typically assessed during delayed-based filtering?

Delayed-based filtering is a method used to assess the legitimacy of an email, particularly by analyzing the timing of the greeting banner, which is the initial response from the sending server. This timing provides insights into how prompt the server is in acknowledging the email request. A legitimate server typically responds quickly, reflecting a well-configured system. In contrast, suspicious servers, which may be involved in sending spam or malicious emails, often show delays in this process.

This assessment helps email filtering systems determine whether to allow the message through or flag it as potentially harmful. Understanding this aspect is crucial for maintaining effective email security and preventing unwanted communications.