What this tool can and cannot do
DKIM keys are stored under a "selector" name that only the sender knows. Enter your selector if you know it; otherwise we try common selectors used by major email providers, which may miss custom ones.
Data sources: Public DNS-over-HTTPS resolvers
Understanding the results
SPF lists who may send mail for the domain and should end in ~all or -all. DMARC tells receivers what to do when checks fail: p=none (monitor), p=quarantine (spam folder) or p=reject (block).
Troubleshooting
- SPF has a limit of 10 DNS lookups; too many include: statements will make SPF fail.
- Start DMARC at p=none with a reporting address, then move to quarantine/reject once reports look clean.
Frequently asked questions
Do I need all three?
Yes. Major mailbox providers now require SPF or DKIM plus DMARC for bulk senders, and all three together give the best protection.