How does turning on DKIM impact domain reputation and email deliverability?

Summary

Implementing DKIM is crucial for enhancing email deliverability and protecting domain reputation. It verifies the sender's identity, preventing spoofing and ensuring messages aren't altered in transit. While DKIM generally builds trust with email providers and improves inbox placement, initial implementation can sometimes cause temporary deliverability issues, including deferrals and potential resets of existing unsigned domain reputation. DKIM achieves this by adding an encrypted signature to email headers, which receiving systems use to authenticate messages. Correct configuration and continuous monitoring are essential, and integrating DKIM with DMARC provides enhanced domain protection. Unsigned domains remain invisible in Google Postmaster Tools (GPMT), highlighting the significance of authentication for reputation tracking. Treat initial DKIM implementation as a warm-up process and, if possible, add an additional signature with the client's domain.

Key findings

  • Authentication and Trust: DKIM authenticates email messages, verifying the sender's identity and building trust with email providers.
  • Deliverability Enhancement: Proper DKIM implementation improves email deliverability and reduces the likelihood of messages being marked as spam.
  • Configuration Sensitivity: Incorrect DKIM setup can negatively impact deliverability, requiring careful configuration and continuous monitoring.
  • Domain Reputation Protection: DKIM protects domain reputation by preventing spoofing and phishing attacks.
  • GPMT Visibility Requirement: Unsigned domains do not appear in Google Postmaster Tools, emphasizing the importance of DKIM for monitoring deliverability.
  • Additional Signatures: If possible, add an additional signature with the client's domain.

Key considerations

  • Warm-up Approach: Treat the initial DKIM implementation as a warm-up process to avoid sudden deliverability issues.
  • Configuration Accuracy: Ensure accurate DKIM configuration to prevent negative impacts on deliverability and sender reputation.
  • Continuous Monitoring: Continuously monitor DKIM performance and deliverability metrics to identify and address any issues promptly.
  • DMARC Integration: Integrate DKIM with DMARC for enhanced domain protection and improved email deliverability.
  • Reputation Tracking Tool: Utilize Google Postmaster Tools to monitor domain reputation and identify potential deliverability problems; note that unsigned domains are not visible.

What email marketers say
12Marketer opinions

Implementing DKIM significantly impacts domain reputation and email deliverability. While it generally helps build trust with email providers by verifying the sender's legitimacy and preventing spoofing, improper setup or initial implementation can sometimes lead to temporary deliverability issues, including deferrals and reputation resets. DKIM works by adding an encrypted signature to email headers, which receiving servers use to verify the message's authenticity. Combined with DMARC, DKIM further protects the domain and improves inbox placement. However, it's crucial to ensure correct configuration and monitoring to avoid potential negative impacts on deliverability. Unsigned domains don't appear in Google Postmaster Tools, emphasizing the importance of authentication for reputation tracking.

Key opinions

  • Trust Building: DKIM builds trust with email providers by verifying the legitimacy of the sender and preventing spoofing.
  • Deliverability Improvement: Properly implemented DKIM increases the likelihood of emails reaching the inbox and reduces the risk of being marked as spam.
  • Configuration Importance: Incorrect DKIM setup can negatively impact deliverability, highlighting the need for careful configuration and monitoring.
  • Reputation Impact: Adding DKIM can sometimes reset existing unsigned domain reputation.
  • GPMT Visibility: Unsigned domains do not appear in Google Postmaster Tools (GPMT), emphasizing the importance of DKIM for tracking reputation.

Key considerations

  • Warm-up Process: Treat initial DKIM implementation as a warm-up process to avoid sudden deliverability issues.
  • Correct Configuration: Ensure DKIM is correctly configured to prevent negative impacts on deliverability.
  • Monitoring: Continuously monitor DKIM performance and deliverability metrics to identify and address any issues promptly.
  • DMARC Combination: Implement DKIM in conjunction with DMARC for enhanced domain protection and improved email deliverability.
  • Reputation Tracking: Use Google Postmaster Tools (GPMT) to monitor domain reputation and identify potential deliverability problems, recognizing that unsigned domains won't be visible.
Marketer view

Email marketer from Sendinblue explains that DKIM helps mailbox providers identify and filter spam. By implementing DKIM, you demonstrate that you are a legitimate sender, reducing the likelihood of your emails being marked as spam.

February 2024 - Sendinblue
Marketer view

Email marketer from Reddit explains that implementing DKIM without proper setup can negatively affect deliverability temporarily, emphasizing the importance of correct configuration and monitoring.

October 2022 - Reddit
Marketer view

Email marketer from Litmus explains that DKIM authentication helps to prove that you're a legitimate sender and improves trust in your email program. This reduces the chances that mailbox providers will mark your messages as spam.

July 2021 - Litmus
Marketer view

Marketer from Email Geeks explains that implementing DKIM may cause a new fingerprint in the Machine Learning, leading to potential issues.

March 2023 - Email Geeks
Marketer view

Email marketer from HubSpot shares that DKIM ensures that your email messages aren't altered in transit, which helps protect your reputation and build trust with recipients. By authenticating your emails, you reduce the risk of your messages being flagged as spam.

July 2024 - HubSpot
Marketer view

Marketer from Email Geeks mentions that adding another DKIM signature has caused issues for senders that haven't signed before, and it has felt like DKIM resets any existing unsigned domain rep.

March 2025 - Email Geeks
Marketer view

Marketer from Email Geeks states that unsigned domains do not show up in Google Postmaster Tools (GPMT).

November 2023 - Email Geeks
Marketer view

Email marketer from Mailjet shares that DKIM helps build trust with email providers, as it verifies that the email genuinely comes from your domain. This trust can improve your sender reputation and, subsequently, your deliverability rates.

April 2022 - Mailjet
Marketer view

Email marketer from Email Marketing Forum shares that DKIM is a crucial factor for improving email deliverability, ensuring that the recipient mail server can verify that the email was indeed sent from the domain it claims to be from.

November 2022 - Email Marketing Forum
Marketer view

Email marketer from Postmark shares that implementing DKIM and DMARC helps protect your domain's reputation and ensures that your emails are more likely to reach the inbox. By authenticating your emails, you are sending a clear signal to mailbox providers that you are a legitimate sender.

February 2024 - Postmark
Marketer view

Email marketer from ActiveCampaign explains that DKIM helps you build a good sender reputation by demonstrating to email providers that you are a legitimate sender. This can lead to better deliverability and inbox placement.

December 2022 - ActiveCampaign
Marketer view

Marketer from Email Geeks shares that they have seen instances where turning on DKIM for the first time has caused deferrals from Gmail, suggesting that it should be treated as a warm-up process.

January 2023 - Email Geeks

What the experts say
3Expert opinions

DKIM significantly impacts email deliverability by providing authentication mechanisms. It allows receiving mail servers to verify that an email originates from the claimed domain, which prevents spoofing and phishing attacks. Adding an additional signature with the client's domain can be beneficial. By confirming the sender's identity, DKIM helps improve sender reputation and overall deliverability.

Key opinions

  • Authentication: DKIM authenticates email messages, confirming the sender's identity.
  • Spoofing Prevention: DKIM prevents spoofing and phishing attacks by verifying the email's origin.
  • Deliverability Improvement: Verifying sender's legitimacy can help improve sender reputation and overall deliverability.
  • Additional Signatures: ESPs should allow adding an additional signature with the client's domain, if possible.

Key considerations

  • Implementation: Implement DKIM to authenticate email messages and improve sender reputation.
  • ESP Support: Check if the ESP allows adding an additional signature with the client's domain.
  • Anti-Spoofing: Use DKIM to prevent spoofing and phishing attempts.
Expert view

Expert from Email Geeks suggests that if possible, the ESP should allow adding an additional signature with the client's domain.

June 2023 - Email Geeks
Expert view

Expert from Spam Resource explains that DKIM can help improve deliverability by allowing receiving mail servers to verify that an email truly originated from the domain it claims to be from. This helps to prevent spoofing and phishing attacks, and can improve your sender reputation.

January 2022 - Spam Resource
Expert view

Expert from Word to the Wise responds that DKIM helps to authenticate email messages, making it more difficult for spammers to forge the 'From' address and improving deliverability by confirming the sender's identity.

September 2023 - Word to the Wise

What the documentation says
5Technical articles

DKIM improves email deliverability by providing an authentication method that verifies the sender's identity and ensures message integrity. By adding an encrypted signature to email headers, receiving systems can confirm that the message hasn't been altered and originates from the claimed domain, preventing sender address forgery. This authentication process helps build trust, improves email security, and reduces the likelihood of messages being marked as spam. DKIM is a crucial component of an overall email authentication strategy.

Key findings

  • Sender Verification: DKIM allows email systems to verify that a message truly originated from the claimed domain.
  • Integrity Assurance: DKIM ensures that the message was not altered after it was sent by the sender.
  • Forgery Prevention: DKIM helps prevent attackers from forging the sender address in email messages.
  • Trust Building: By authenticating messages, DKIM increases the trustworthiness of emails, leading to better delivery rates.
  • Spam Reduction: Without DKIM, messages from your domain are more likely to be marked as spam.

Key considerations

  • Implementation: Implement DKIM to ensure messages are correctly delivered and not marked as spam.
  • Encryption: Understand the encryption process involved in DKIM to ensure the integrity and authentication of email messages.
  • Authentication Strategy: Consider DKIM as a crucial part of a broader email authentication strategy for optimal deliverability.
  • RFC Compliance: Adhere to the DKIM standard (as specified by the RFC Editor) for consistent and reliable implementation.
Technical article

Documentation from dmarcian explains that DKIM provides a mechanism to validate the source and integrity of email messages. While DKIM alone does not guarantee improved deliverability, it's a crucial component of a broader email authentication strategy that can positively influence inbox placement.

July 2021 - dmarcian
Technical article

Documentation from Microsoft explains that DKIM adds an encrypted signature to the header of email messages. Email systems that receive DKIM-signed email use the public key to verify that the message was not altered after it was sent. Without DKIM, messages sent from your domain might be marked as spam.

December 2024 - Microsoft
Technical article

Documentation from AuthSMTP explains the DKIM is useful in the correct identification of the sender - making the e-mail appear more trustworthy and in effect improving the delivery rate.

September 2021 - AuthSMTP
Technical article

Documentation from Google explains that DKIM helps prevent attackers from forging the sender address in your messages. This increases the chances that your messages are correctly delivered.

November 2023 - Google
Technical article

Documentation from RFC Editor specifies the DKIM standard, detailing how it provides an authentication method for verifying the domain name identity associated with a message, improving overall email security and trust.

July 2023 - RFC Editor