SPF Record Checker
Look up your SPF record and count how many DNS lookups it requires. The RFC limit is 10 — exceeding it causes silent email authentication failures.
What is SPF?
SPF (Sender Policy Framework) is a DNS TXT record that specifies which mail servers are authorised to send email for your domain. When a receiving server gets an email claiming to be from your domain, it checks your SPF record to verify the sender is legitimate.
A common issue is exceeding the 10 DNS lookup limit. Each include:, a:, mx:, and redirect= mechanism counts as a lookup. Nested includes add up quickly — especially when using multiple email services.