A company wants to minimize the chance of its outgoing marketing emails getting flagged as spam. The company decides to list the email servers on the proper DNS record. Which of the following protocols should the company apply next?

DMARC (Domain-based Message Authentication, Reporting & Conformance) is a protocol that builds on SPF and DKIM by providing reporting and policy enforcement. While DMARC is important for protecting against phishing and email spoofing, it requires DKIM to be in place first to function effectively. Therefore, applying DMARC alone without DKIM would not sufficiently address the spam issue at this stage.

DLP (Data Loss Prevention) focuses on preventing sensitive data from being sent outside the organization. While DLP is crucial for security and compliance, it does not directly impact the deliverability of marketing emails or their chances of being flagged as spam. Thus, it is not relevant to the specific concern of email authentication.

SPF (Sender Policy Framework) allows domain owners to specify which servers are permitted to send emails on behalf of their domain. While important for reducing spam, SPF alone does not provide the same level of content verification as DKIM and is most effective when used in conjunction with DKIM for higher email deliverability.