Quick Summary
SPF (Sender Policy Framework) is a DNS record standard that identifies servers authorized to send email on behalf of a domain.
SPF (Sender Policy Framework) is a DNS-based authentication standard designed to prevent email spoofing. The domain owner specifies which IP addresses or servers are authorized to send email on their domain's behalf via the SPF record.
How SPF Works
The domain owner adds an SPF TXT record to DNS. When an email is received, the receiving server checks whether the sender's IP address is listed in the SPF record. Emails from unauthorized servers are marked as spam or rejected.
SPF DNS Record Example
example.com TXT "v=spf1 ip4:203.0.113.1 include:mail.example.com ~all"
ONS Mail SPF Support
ONS Mail provides automatic SPF record creation and validation tools.