A few weeks after deploying additional email servers, a company begins to receive complaints that...

When new email servers are deployed, organizations must update their SPF (Sender Policy Framework) records to list the new servers as authorized senders. If the SPF DNS record does not include the new IP addresses, recipient mail systems cannot verify the legitimacy of the messages, causing them to be flagged as spam or rejected.

Security+ SY0-701 identifies SPF as a key email authentication mechanism responsible for preventing:

Email spoofing

Unauthorized sender impersonation

False spam detection

Domain reputation issues

CNAME (A) maps domain aliases but does not authenticate email. SMTP (B) is the mail protocol and does not influence spam classification. DLP (C) prevents data leakage, not spam filtering.

Updating the SPF record resolves legitimacy issues by informing receiving mail servers that the new email servers are trusted.

Thus, the correct answer is D: SPF.