Several measures can be taken to protect against email spoofing:
SPF (Sender Policy Framework): This protocol allows domain owners to specify which mail servers are permitted to send emails on their behalf. It helps detect and block spoofed emails. DKIM (DomainKeys Identified Mail): This adds a digital signature to emails, which can be verified by the recipient's mail server to ensure the email's authenticity. DMARC (Domain-based Message Authentication, Reporting & Conformance): This builds on SPF and DKIM, allowing domain owners to publish policies on how to handle emails that fail authentication checks and to receive reports on email delivery.