By ToolzHive
About this tool
Look up and validate a domain's SPF record, count DNS lookups and explain every mechanism.
How to use SPF Record Checker
- Enter the domain you send email from.
- Click Check SPF. Every include is followed so the total DNS lookup count is accurate.
- Fix any failed checks, such as more than one SPF record, more than 10 lookups or a missing ~all or -all at the end.
Worked example
A record like v=spf1 include:_spf.google.com include:sendgrid.net ~all passes when both services are used. If adding a fifth service pushes the count past 10 lookups, receivers return a PermError and SPF stops protecting you.
What is the 10 DNS lookup limit?
SPF allows at most 10 mechanisms that need DNS lookups (include, a, mx, ptr, exists and redirect), counting nested includes. Going over makes SPF fail.
Should I use ~all or -all?
Start with ~all (soft fail) while you confirm every sender is listed, then move to -all (hard fail) for the strongest protection. Never use +all.
Can a domain have two SPF records?
No. Two v=spf1 TXT records cause a permanent error. Merge them into one record.
Put this guide into practice
- SPF Record Checker — Look up and validate a domain's SPF record, count DNS lookups and explain every mechanism.