What does SPF stand for?
SPF stands for Sender Policy Framework. An email authentication record in DNS listing which servers may send mail for a domain.
SPF lets a domain owner publish, in a DNS TXT record, the servers that are allowed to send mail for the domain. A receiving server looks up the record for the domain in the envelope sender, the address used in the SMTP conversation, and checks whether the connecting server is listed. SPF is defined in RFC 7208, which also limits a check to ten DNS lookups.
SPF in practice: an example
example.com publishes v=spf1 include:_spf.mailprovider.example -all. A message claiming to be from example.com arrives from a server that is not covered by the record. The SPF check fails, and the receiver uses that result, together with DMARC, to decide whether to reject it.
What SPF is confused with
SPF vs DKIM: what is the difference?
SPF checks which server sent the message. DKIM checks a cryptographic signature on the message itself. What DKIM stands for
SPF vs DMARC: what is the difference?
SPF by itself does not look at the From address the user sees. DMARC adds that check, called alignment, and tells receivers what to do on failure. What DMARC stands for
Which exams cover SPF?
SPF is on the official CompTIA acronym list for three of the four exams covered here.
- Security+ SY0-801: 4.1 (Security Operations).
- CySA+ CS0-004: on the acronym list, not tied to one objective.
- A+ 220-1201 and 220-1202: 220-1201 2.0 (Networking).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. A company starts sending newsletters through a new provider and the messages fail SPF. What is the fix?
- Add the provider's sending servers to the domain's SPF record
- Change the MX record to the provider
- Disable TLS on the mail server
- Shorten the subject lines
Show the answer
A. Add the provider's sending servers to the domain's SPF record. SPF passes only for servers listed in the sender domain's record, so the new provider must be authorized there.
2. Where is an SPF policy published?
- In a DNS TXT record of the sending domain
- In the message body
- On the recipient's firewall
- In the browser certificate store
Show the answer
A. In a DNS TXT record of the sending domain. Receivers look the policy up in DNS under the domain of the envelope sender.
Sources: RFC 7208: Sender Policy Framework (SPF); NIST SP 800-177 Rev. 1, Trustworthy Email. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 11 November 2026.