How to find your DKIM selector
find DKIM selector · DKIM selector lookup · Google Workspace DKIM selector
Practical places to find DKIM selectors in Google Workspace, Microsoft 365, Amazon SES, Mailchimp, SendGrid and email headers.
Por DN01 Network Team
The domain alone is not enough for DKIM validation; the selector usually comes from your mail provider, DNS setup screen, or the DKIM-Signature header. DKIM prova que a mensagem foi assinada pelo remetente e que a chave pública está publicada no DNS.
Guessing default selectors can hide the active key, especially after migrations where old selectors remain published during rotation. Verifique o nome exato selector._domainkey.domínio: sem selector não há como saber qual chave o receptor deve usar.
Start with selectors such as google, selector1, selector2, k1, s1 or s2 only when your provider documentation confirms them, then verify the exact name in /pt/dkim-validator. Confira o TXT, as tags v/k/p/h/s/t, o tamanho da chave, t=y e revoked; depois compare com DNS Checker.
What to verify first
Confirm that the selector is copied from the mail provider, not guessed from another domain or an old migration note.
Check whether the answer is a direct TXT record or a CNAME chain that eventually points at the DKIM TXT value.
Look at v=DKIM1, k=, p=, h=, s= and t= together. A record can exist but still be unusable when the public key is empty, malformed or too weak.
Common failure causes
The record was added to the wrong DNS provider, while the domain still delegates to another authoritative nameserver.
The selector changed during a provider migration, key rotation or domain re-verification, but an older selector is still being tested.
The TXT value was split or quoted incorrectly by a DNS editor, so receivers cannot reconstruct the base64 public key.
How to fix safely
Publish the new key first, wait for DNS visibility, then switch signing in the provider console. Do not delete the old selector until delayed mail has cleared.
Use t=y only during rollout. Once signed mail verifies consistently, remove testing mode so DKIM sends a stronger production signal.
Keep DKIM checks next to SPF and DMARC checks. A valid DKIM key is one part of deliverability, not the whole authentication policy.
| Tag | Why it matters |
|---|---|
| v=DKIM1 | Identifies the TXT value as a DKIM record. |
| p= | Carries the public key; an empty value revokes the key. |
| k= | Declares the key type, commonly rsa or ed25519. |
| h= | Limits allowed hash algorithms such as sha256. |
| t= | Flags testing mode (y) or strict subdomain behavior (s). |
Perguntas frequentes
- Can I check DKIM without a selector?
No. DKIM records are selector-specific, so you need the selector from your provider or from a DKIM-Signature header.
- Why is the DKIM record found but invalid?
The TXT record may have a wrong version tag, duplicate tags, missing p=, invalid base64, a revoked empty key or a weak/malformed public key.
- Should I keep the old selector during rotation?
Yes, keep it until TTLs and delayed mail queues clear. Removing it too early can break verification for messages already in transit.