Generador de claves DKIM
Generate a DKIM key pair, get the DNS record and private key it produces, or paste a record you already have and check it. The key pair is generated locally in your browser and never sent anywhere.
¿Qué es DKIM?
DKIM (DomainKeys Identified Mail) attaches a digital signature to every message you send, using a private key only your mail server knows. The receiving mailbox looks up the matching public key in your DNS and checks the signature, proof the message really came from you and wasn't altered in transit.
The key pair is generated once. The private key stays on your mail server or your email service provider, where it signs outgoing mail. The public key goes into a DNS TXT record at a location called the selector. That's the only part this tool publishes for you.
Selector
A short name that lets you run more than one key at once, useful for rotating keys or running several sending services side by side.
Clave pública (DNS)
Published as a TXT record at selector._domainkey.yourdomain.com. Anyone can look it up: that's the point.
Clave privada (tu servidor)
Se mantiene en secreto y se instala donde realmente se firma tu correo. Nunca la publiques ni la envíes a ningún otro lugar.
DKIM on its own only proves a message wasn't tampered with. It's DMARC that decides what happens when a message fails. Once DKIM is signing cleanly, the DMARC policy generator is the natural next step.
Genera tu clave
Fill in your domain and selector, pick a key size, and generate. The DNS record on the right updates with it. Already have a record? Paste it in to check it.
Generar un par de claves
Runs entirely in your browser. The private key is never sent anywhere.
Tamaño de clave
2048 bits es la recomendación actual. 1024 bits es más débil pero más corto, lo cual importa si tu proveedor de DNS tiene problemas con registros TXT largos.
Restringir hashes a SHA-256
hOnly allow SHA-256 signatures. Leaving this off also accepts the older, weaker SHA-1. Most senders should keep this on.
Restringir a correo electrónico
sLimita esta clave a firmar correo electrónico, para que no pueda reutilizarse para firmar cualquier otra cosa que verifique la etiqueta s.
Modo de prueba
t=yAsk receivers not to act on a signature failure yet. Useful while you roll this out. Turn it off once mail is signing and passing cleanly.
Coincidencia estricta de subdominio
t=sRequiere que el dominio de firma coincida exactamente con tu dominio From, para que esta clave no pueda usarse para firmar en nombre de un subdominio.
Clave privada
Genera un par de claves para ver tu clave privada aquí.
Registro DNS
Publica este registro TXT en tu dominio.
Add this as a new record at your DNS provider. “Type” and “Host” are the fields it asks for. Some providers want just mail._domainkey in the host field and add the domain for you.
Paste an existing record here to check it. It won't recover a private key.