Question 1

What is an SPF record?

Accepted Answer

Sender Policy Framework (SPF) is an email authentication standard published in your DNS TXT records. It specifies which mail servers and IP addresses are authorized to send email on behalf of your domain name.

Question 2

What is the 10-lookup SPF limit?

Accepted Answer

RFC 7208 strictly limits the number of recursive DNS lookups during SPF evaluation (mechanisms such as include, a, mx, ptr, and redirect) to 10. If an SPF record requires more than 10 DNS lookups, major providers like Google and Microsoft will fail the check with a PermError.

Question 3

Why should I monitor my SPF record?

Accepted Answer

Third-party email tools, SaaS platforms, or team members often add new include directives that silently push your lookup count past 10, causing legitimate emails to fail authentication and land in spam folders.

SPF Record Checker & Syntax Validator