Email Authentication: how to authenticate your emails

Updated 16 October 2026. Email authentication helps a receiving service check which domainIn technical terms, a domain name is the address used to visit a specific website.... More authorized a message. SPF, DKIMDKIM is an email authentication method based on a digital signature. The acronym stands for... More and DMARCDMARC is the system created to ensure email compliance and integrity. Short for Domain-Based Message... More address different parts of that check. They reduce opportunities for impersonation, but a passing result does not guarantee inbox placement or prove that a message is safe.

What SPF, DKIM and DMARC check

• SPF checks whether the sending IP is authorized to use the envelope sender domainIn technical terms, a domain name is the address used to visit a specific website.... More (or HELO identity in relevant cases). That domainIn technical terms, a domain name is the address used to visit a specific website.... More can differ from the visible From address. The protocol is defined in RFC 7208.
• DKIMDKIM is an email authentication method based on a digital signature. The acronym stands for... More verifies a cryptographic signature against a public key published for the signing domainIn technical terms, a domain name is the address used to visit a specific website.... More and selector. A valid signature checks the signed parts of the message, rather than every possible change or the identity of a human author. See RFC 6376.
• DMARCDMARC is the system created to ensure email compliance and integrity. Short for Domain-Based Message... More connects the visible From domainIn technical terms, a domain name is the address used to visit a specific website.... More to a passing SPF or DKIMDKIM is an email authentication method based on a digital signature. The acronym stands for... More result through domainIn technical terms, a domain name is the address used to visit a specific website.... More alignment. A domainIn technical terms, a domain name is the address used to visit a specific website.... More owner can publish a policy and request reports; receivers apply their own handling rules. See RFC 7489.

Check a domain, then check a received message

1. List every service that sends for your domainIn technical terms, a domain name is the address used to visit a specific website.... More: your business mailbox, website, transactional relay and marketing platform. Obtain each provider’s current DNS instructions.
2. Use the free MailSenpai email DNS checker to inspect public records. Add the DKIMDKIM is an email authentication method based on a digital signature. The acronym stands for... More selector supplied by your provider when needed. Finding a record does not prove that actual outgoing mail uses it.
3. Publish changes at the authoritative DNS provider. Check the existing configuration first: do not create a second SPF policy or replace another sender’s authorization blindly. Allow for DNS caching before retesting.
4. Send one real test through each sending service to a mailbox you control. Open the received message’s original headers and inspect Authentication-Results, the signing domainIn technical terms, a domain name is the address used to visit a specific website.... More and the From domainIn technical terms, a domain name is the address used to visit a specific website.... More.
5. Retest website notifications as well as manual messages. For WordPress, follow the API or SMTP setup and troubleshooting guide. Keep keys and customer addresses out of screenshots.

Authentication, spam tests and list validation

These answer different questions. Authentication checks the sending identity and its alignment. A spam test examines a particular message and reports checks that may need attention. Address validation evaluates recipient addresses; it does not configure SPF, sign outgoing messages or make DMARCDMARC is the system created to ensure email compliance and integrity. Short for Domain-Based Message... More pass. None of these tools guarantees delivery to every inbox.

A passing result is the start of monitoring

Keep a record of the sender, date, transport, authentication result and any delivery error. Inspect DMARCDMARC is the system created to ensure email compliance and integrity. Short for Domain-Based Message... More reports before tightening a policy, so legitimate senders are not accidentally excluded. Investigate bounces and complaints, and protect mailbox access separately with strong authentication. DomainIn technical terms, a domain name is the address used to visit a specific website.... More authentication does not prevent every phishing message or protect a compromised account.

For mail sent to personal Gmail accounts, consult Google’s current sender guidelines. Requirements differ for all senders and high-volume senders; transport security, message formatting, spamSpam is unwanted messaging: messages sent, often repeatedly, to recipients who never asked to receive... More rates and unsubscribe handling also matter. Follow the current rules of each receiving provider.

Using SMTP Senpai? Verify your sender domainIn technical terms, a domain name is the address used to visit a specific website.... More in the customer area and use the DNS values shown for that account. The API documentation and integration guides explain how to connect an application and read errors. Relay acceptance and delivery to the recipient server remain distinct from inbox placement.