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DNS Setup for Authentication

The Importance of DNS Setup for Email Authentication

DNS (Domain Name System) plays a crucial role in email authentication, ensuring that your emails are trusted, secure, and successfully delivered. Without a proper DNS setup, your emails may be flagged as spam, rejected, or even exploited by attackers.

Here’s why DNS configuration is essential for email authentication:

DNS as the Foundation of Email Authentication

Email authentication methods—SPF, DKIM, DMARC, and BIMI—all rely on DNS TXT records to verify your email-sending identity. These records help email providers identify legitimate senders and block malicious attempts (e.g., phishing and spoofing attacks).

SPF, DKIM, DMARC and BIMI explained

 

Understanding and Implementing SPF, DKIM, DMARC, and BIMI

Email authentication is essential for preventing phishing, spam, and spoofing. The four key authentication protocols—SPF, DKIM, DMARC, and BIMI—help ensure that your emails are trusted and delivered successfully. Below, we explain what each does, how to implement them, and how to test your setup.

1. SPF (Sender Policy Framework)

What SPF Does

SPF prevents spammers from sending emails on behalf of your domain. It specifies which mail servers are authorized to send emails from your domain.

How to Implement SPF

  1. Create an SPF record in your domain's DNS settings (TXT record).
  2. Use this format:iniv=spf1 ip4:192.168.1.1 include:_spf.example.com -all
    • Replace 192.168.1.1 with your authorized IP address.
    • Replace _spf.example.com with any email service provider you use (e.g., Google, Microsoft).
    • The -all at the end means emails from unauthorized servers should be rejected.
  3. KopiérRediger

How to Test SPF

  • Use test.smtp.ai to verify if SPF is correctly set up.
  • Look for "SPF Pass" in the test results.

2. DKIM (DomainKeys Identified Mail)

What DKIM Does

DKIM adds a digital signature to your emails, ensuring that they haven’t been tampered with during transmission.

How to Implement DKIM

  1. Enable DKIM in your email provider’s settings (e.g., Google Workspace, Microsoft 365).
  2. Your provider will generate a DKIM public key.
  3. Add the DKIM record as a TXT record in your domain’s DNS, like this:iniv=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3...
    • The "p=" value is your public key.
  4. KopiérRediger

How to Test DKIM

  • Run a test on test.smtp.ai to confirm DKIM is correctly set up.
  • If DKIM is working, you’ll see "DKIM Pass" in the test results.

3. DMARC (Domain-based Message Authentication, Reporting, and Conformance)

What DMARC Does

DMARC tells receiving mail servers how to handle emails that fail SPF or DKIM checks. It also provides reporting to monitor authentication failures.

How to Implement DMARC

  1. Create a DMARC TXT record in your domain’s DNS.
  2. Use this format:iniv=DMARC1; p=reject; rua=mailto:This email address is being protected from spambots. You need JavaScript enabled to view it.
    • p=reject ensures that unauthorized emails are blocked.
    • rua=mailto:This email address is being protected from spambots. You need JavaScript enabled to view it. receives DMARC failure reports.
  3. KopiérRediger

How to Test DMARC

  • Use test.smtp.ai to verify your DMARC settings.
  • Look for "DMARC Pass" in the test results.

4. BIMI (Brand Indicators for Message Identification)

What BIMI Does

BIMI allows you to display your brand logo next to your emails in supported email clients.

How to Implement BIMI

  1. Ensure DMARC is fully implemented and set to quarantine or reject.
  2. Create an SVG logo that meets BIMI specifications.
  3. Obtain a Verified Mark Certificate (VMC) (some email providers require this).
  4. Publish a BIMI TXT record in your domain’s DNS:iniv=BIMI1; l=https://example.com/logo.svg; a=https://example.com/vmc.pem
    • l= is the URL to your logo.
    • a= is the URL to your VMC certificate (if required).
  5. KopiérRediger

How to Test BIMI

  • BIMI is not yet supported by all email clients.
  • Use test.smtp.ai to check if your BIMI setup is correct.

Final Testing & Monitoring

After implementing SPF, DKIM, DMARC, and BIMI, always test and monitor your settings:
✅ Check your records using test.smtp.ai.
✅ Review DMARC reports to monitor unauthorized email activity.
✅ Ensure your emails are delivered correctly and not marked as spam.

By setting up these authentication protocols properly, you can protect your email domain, improve deliverability, and build trust with recipients.