How SPF works in Microsoft 365 – protection against email spoofing
The Sender Policy Framework (SPF) in Microsoft 365 helps prevent unauthorized people from sending emails in the company’s name. By defining which servers are allowed to send email for the domain, receiving systems can verify that the sender is legitimate. Together with DMARC and DKIM, SPF strengthens email security, reduces the risk of spam and phishing, and protects your company’s reputation.
Background and overview
SPF is an email security standard that helps verify that incoming messages come from authorized sources. In Microsoft 365, SPF is used as part of a broader strategy to protect against email spoofing and phishing attacks.
What is SPF?
Sender Policy Framework (SPF) is a DNS-based method that specifies which mail servers are allowed to send email for a given domain.
How SPF works in practice
When an email is received, the receiving server checks the SPF record for the domain. If the sender’s server is not authorized, the message is marked as potentially false.
SPF and Microsoft 365
Microsoft 365 automatically provides SPF records for domains that use the service. Administrators can customize the SPF record to include third-party providers that send email for the company.
Benefits of the SPF
SPF reduces the risk of phishing and spam, protects your company’s brand and improves the deliverability of legitimate email.
SPF together with DKIM and DMARC
Together with DKIM (digital signature) and DMARC (policy and reporting), SPF contributes to strong email authentication and reduces the risk of forged messages.
Implementation and monitoring
Administrators should regularly review and update SPF records, monitor reports, and ensure that changes to third-party servers are accurately reflected.
Common mistakes
Common errors include not including all email sources, overly long SPF records, or syntactic errors that can cause legitimate messages to be flagged.
Key points about SPF in Microsoft 365
- DNS-based verification: Specifies which servers are allowed to send emails for the domain.
- Anti-spoofing protection: Reduces phishing and spam.
- Integration with Microsoft 365: SPF records are automatically created but can be customized.
- In conjunction with DKIM and DMARC: Enhances email security and delivery reliability.
- Regular monitoring: Ensures that changes in email sources are correctly reflected.
- Brand protection: prevents attackers from sending emails in the company’s name.
Related questions
What is SPF in Microsoft 365?
SPF is a DNS-based method that verifies that incoming mail comes from authorized servers for the domain.
How to implement the SPF?
The administrator adds an SPF record to the DNS that lists authorized mail servers, including Microsoft 365 and any third-party providers.
What is the difference between SPF, DKIM and DMARC?
SPF authenticates the server, DKIM digitally signs the message and DMARC sets policy and enables reporting.
Can SPF prevent all phishing?
No, SPF reduces the risk but should be combined with DKIM, DMARC and user training for maximum protection.
What happens if the SPF is not configured correctly?
Incorrect SPF records can lead to legitimate messages being marked as spam or not delivered.
