SPF (Sender Policy Framework) is a DNS record that tells receiving mail servers which servers are allowed to send email on behalf of your domain. If a server not on that list sends email claiming to be from your domain, the receiving server can reject or flag it.
Understanding the syntax makes it easier to set it up correctly and avoid common mistakes like accidentally hitting the 10-lookup limit.
The basic structure
An SPF record is a TXT record on your domain's DNS. It always starts with:
v=spf1
