Setting Up SPF, DKIM and DMARC for Your Cold Email Campaign

Wondering why your carefully crafted messages end up in the spam folder or never reach their intended recipients? Well, we’ve got the answer for you: SPF, DKIM, and DMARC.

These seemingly cryptic acronyms hold the key to email authentication and can save your messages from the abyss of the spam folder.

But what exactly are SPF, DKIM, and DMARC? In simple terms, they are a trio of powerful email security protocols that work together to ensure your emails are delivered reliably and that the recipients can trust their authenticity.

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So, if you’re tired of your important messages disappearing into the black hole of the internet, join us as we unravel the secrets of SPF, DKIM, and DMARC and discover how they can make your email communication smoother and more secure than ever before.

The Fundamentals of SPF, DKIM, and DMARC

Email security has always been a critical concern for domain owners and email servers. With phishing attacks and domain spoofing becoming more sophisticated, it’s vital to implement robust authentication methods like SPF, DKIM, and DMARC.

Understanding SPF (Sender Policy Framework)

SPF, or Sender Policy Framework, is an email authentication protocol that helps protect email senders and receivers from spam, phishing, and other forms of email fraud. It’s a DNS TXT record that domain owners use to specify which IP addresses are authorized to send email and receive messages, on their behalf.

When an email is sent, the receiving server checks the SPF record of the sender’s domain. If the IP address of the sending mail server is listed in the domain’s SPF record, the SPF authentication will pass, and the email will likely avoid the spam folder. If the IP address is not listed in the SPF record, then the email may be marked as spam, or the SPF authentication will fail, affecting your email deliverability.

Unpacking DKIM (DomainKeys Identified Mail)

DKIM, short for DomainKeys Identified Mail, is another domain-based message authentication method that prevents email spoofing. It uses a pair of keys – a private key to encrypt or sign the outgoing messages, and a public key, stored as a DNS TXT record, to decrypt or verify the email message upon receipt.

When an email is sent, the mail server uses the private key to generate a unique DKIM signature for the email message. The receiving mail server uses the public key to validate the DKIM signature, confirming that the email has not been tampered with during transit. If the DKIM authentication passes, the email is accepted; otherwise, it may end up in the spam folder.

This dual key system is an example of cryptographic authentication. This process prevents domain spoofing by ensuring that only emails with a valid DKIM signature, signifying they originated from an authorized domain, are delivered to the recipient’s inbox.

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

DMARC, which stands for Domain-based Message Authentication, Reporting, and Conformance, builds upon both SPF and DKIM. It provides a framework for domain owners to specify how mail servers should handle unauthenticated mail – messages that fail SPF and/or DKIM checks.

A DMARC record is a DNS TXT record that domain owners publish in their DNS records. It instructs the receiving server how to deal with email messages that fail SPF or DKIM authentication checks, such as report them, quarantine them to the spam folder, or reject them outright.

DMARC also provides a reporting mechanism that allows domain owners to receive feedback from email servers about the messages they’re sending. This reporting feature helps domain owners identify and address any issues with their SPF and DKIM setup.

Through the proper implementation of SPF, DKIM, and DMARC, domain owners can significantly enhance their email security, email deliverability, and protect their domain from being used in phishing attacks and email spoofing.

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Remember, protecting your email signing domain’s reputation is essential in the world of cold email outreach. It ensures your messages reach the recipient’s inbox and not the spam folder. Use Mailarrow, our cold email outreach software, to manage your email campaigns effectively. It supports the implementation of all these email security protocols and much more. Sign up for Mailarrow today!

The Differences and Interplay Among SPF, DKIM, and DMARC

While SPF, DKIM, and DMARC may seem similar, each email security protocol serves a distinct role in email validation and authentication. Understanding these differences can provide a clearer picture of how these protocols work together to enhance email security.


Although both SPF and DKIM aim to verify email sender identities and prevent email spoofing, they approach this task differently. SPF uses a list of authorized IP addresses in a SPF record to verify the sending mail server, while DKIM uses cryptographic keys for digital signature verification of the email message.

To implement SPF, domain owners list the IP addresses authorized to send emails on their behalf in the DNS records as SPF records. The receiving email server then checks this record to verify the the sender address’s IP.

On the other hand, DKIM involves the use of a private key to create a digital signature for each outgoing email message. This signature is then validated by the receiving mail server using a public, public and private key and published in the sender’s DNS records as a DKIM record. Thus, while SPF focuses on the sending server, DKIM focuses on the email content itself.


SPF and DMARC are two different components of email security that work together to prevent phishing attacks and improve email deliverability. While SPF provides the first layer of defense by verifying the sender’s IP address, DMARC adds a second layer of protection and reporting.

If an email fails the SPF check, it doesn’t necessarily mean it will be rejected. Mail servers handle SPF fails according to their spam policies, and many allow some messages to be delivered despite SPF fails.

However, when DMARC is implemented, domain owners can dictate how to handle such failures. With a DMARC record, the domain owner can instruct the receiving email server to reject or quarantine emails failing SPF or DKIM checks, thus preventing potentially harmful emails from reaching users’ inboxes.

SPF, DKIM and DMARC working together

SPF, DKIM, and DMARC are designed to work together to provide comprehensive email security. Each of them plays a specific role in the process of email validation and authentication.

SPF allows domain owners to specify which IP addresses are allowed to send emails on their behalf, helping email providers to ensure that only authorized servers send mail for their domains.

DKIM provides an encryption key and digital signature that verifies that an email message was not forged or altered.

DMARC unifies the SPF and DKIM authentication mechanisms into a common framework and allows domain owners to define how to handle emails that fail these checks.

By combining SPF, DKIM, and DMARC, you can significantly boost your email deliverability and protect your domain from being misused.

Remember, setting up SPF, DKIM, and DMARC properly is vital for the success of your cold email outreach campaigns. So, don’t leave it to chance. Sign up for Mailarrow, our cold email outreach software, and secure your email campaigns today!

Implementing SPF, DKIM, and DMARC

Now that we understand the importance of SPF, DKIM, and DMARC in ensuring email security and enhancing email deliverability, let’s delve into how you can set up these protocols for your domain.

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Setting up SPF

Creating an SPF record involves the following steps:

  1. Identify the mail servers and IP addresses authorized to send emails on behalf of your domain. These could include your business’s mail server, email service provider, or third-party services that send emails on your behalf.
  2. Create a TXT record in your domain’s DNS settings with this information. The SPF record might look something like this: v=spf1 ip4: ip4: a -all. This SPF record specifies that IP addresses within the range to and the single IP address are authorized to send emails on behalf of your domain.
  3. Regularly update your SPF records as you add or remove authorized IP addresses or mail servers.

Setting up DKIM

To set up DKIM, you need to do the following:

  1. Generate a pair of public and private keys. You keep the private key secure within your sending mail server while the public key will be added to your DNS records.
  2. Configure your email server or email service provider to sign all outgoing messages with the private key. This adds a DKIM signature in the email headers of each outgoing email.
  3. Publish the public key in your domain’s DNS records as a DKIM record. The receiving server will use this public key to verify the DKIM signature of your emails.

Implementing DMARC

Finally, to set up DMARC:

  1. Verify that both SPF and DKIM records are correctly set up and working for your domain.
  2. Create a DMARC record in your domain’s DNS settings. A typical DMARC record may look like this: v=DMARC1; p=reject; rua=mailto:[email protected]. This DMARC policy tells the receiving email server to reject emails failing SPF or DKIM checks and send reports about such incidents to the email address [email protected].
  3. Regularly review DMARC reports to ensure your email delivery is functioning correctly and identify potential authentication issues.

Remember, these are the general steps and might vary depending on your DNS provider or mail services. Always refer to your service provider send mail it’s documentation or consult with a tech professional if you are unsure.

Setting up SPF, DKIM, and DMARC can seem daunting, but it’s a crucial part of maintaining a good email sender reputation and ensuring your cold emails don’t end up in the spam folder. And don’t forget, with Mailarrow, our cold email outreach software, implementing these email security protocols is a breeze. Sign up for Mailarrow today!

Checking SPF, DKIM, and DMARC

After setting up SPF, DKIM, and DMARC for your domain, it’s crucial to regularly check their functionality and maintain their records to ensure continuous email deliverability.

Checking SPF

To verify your SPF record:

  1. Use an SPF check tool available online. You only need to enter your domain name, and the tool will look up the DNS TXT record containing your SPF policy.
  2. Review the report generated by the tool. It should show the SPF record for your domain and whether the syntax is correct.
  3. Conduct a test email send from one of the IP addresses mentioned in your SPF record to ensure the receiving server correctly recognizes it.

Checking DKIM

To confirm your DKIM settings are correct:

  1. Use an online DKIM check tool. Enter your domain name and the selector (a string used in your DKIM settings), and the tool will look up your DNS record to find the DKIM record.
  2. Review the report to confirm the DKIM record’s existence, syntax correctness, and the presence of the public key.
  3. To further verify, send a test email from your domain to a mailbox with DKIM check capability. The email headers should show “DKIM: Pass”.

Checking DMARC

To validate your DMARC setup:

  1. Use a DMARC check tool online. Like with SPF and DKIM, you enter your domain name, and the tool fetches the DMARC record from your DNS.
  2. Evaluate the tool’s report to ensure your DMARC record is found and is syntactically correct.
  3. To test further, try sending an email from a server that isn’t listed in your SPF record or without the DKIM signature. This email should be rejected or quarantined according to your DMARC policy.
  4. Check the email account specified in your DMARC record for reports. The absence of reports may indicate a problem with your DMARC setup.

In conclusion, setting up SPF, DKIM, and DMARC, then checking their functionality, is crucial for your email deliverability, especially for cold email outreach. However, it can be a complex task requiring technical knowledge. That’s where Mailarrow can help. Our cold email outreach software simplifies SPF, DKIM, and DMARC setup, ensuring your emails get to the inbox, not the spam folder. Sign up for Mailarrow now!

SPF, DKIM, and DMARC – The Unseen Guardians of Email Security

We’ve discussed the purpose, differences, setup, and checks for SPF, DKIM, and DMARC. Now let’s dig a little deeper into why these email authentication methods are so critical in today’s world.

Fighting Phishing with SPF, DKIM, and DMARC

Phishing attacks, where scammers send unauthenticated emails pretending to be reputable entities, are on the rise. These can trick recipients into revealing sensitive data or executing malicious actions. Here’s where SPF, DKIM, and DMARC step in.

By implementing SPF, you define a list of authorized IP addresses that can send emails on behalf of your domain, helping prevent domain spoofing. DKIM provides an additional layer of security by using a private key to add a digital signature to your outgoing messages. This cryptographic authentication makes it challenging for fraudsters to alter your email content in transit.

DMARC ties SPF and DKIM together, allowing the domain owner to define how receiving mail servers should handle emails that fail SPF or DKIM checks. Together, these protocols significantly reduce the chances of successful phishing attacks targeting your domain.

Maintaining Email Deliverability

Besides enhancing email security, SPF, DKIM, and DMARC also ensure your emails reach their intended recipients. Email servers use these protocols to filter out spam, which means unauthenticated messages or emails with failed authentication checks often land in the spam folder.

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Implementing SPF, DKIM, and DMARC tells email servers that your emails are legitimate and helps maintain your email sender reputation. This is crucial for email marketing and especially for cold email outreach where email deliverability can make or break your campaign.

In conclusion, SPF, DKIM, and DMARC are the unseen guardians of email security and deliverability. Implementing them may require effort and technical understanding, but the benefits they provide are invaluable.

But remember, you don’t have to do it alone! With Mailarrow, our cold email outreach software, we help you navigate through these complex email security protocols. We ensure that your emails are authenticated, secure, and reach your recipients’ inboxes, not their spam folders. Sign up for Mailarrow today and take your cold email outreach to the next level!


What is SPF, DKIM, and DMARC?

Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-Based Message Authentication, Reporting & Conformance (DMARC) are email authentication protocols that verify an email’s origin and integrity. They help prevent domain spoofing and phishing attacks, ensuring your emails are correctly delivered to recipients’ inboxes.

What is the difference between DMARC and DKIM?

DKIM adds a digital signature to the email headers, which is verified using a public key in the sender’s DNS record. DMARC uses the results of SPF and DKIM checks along with alignment tests to decide how to handle an email based on the policy defined by the domain owner in the DMARC record.

Serge Shlykov is the founder of Mailarrow. Rotterdam Business School graduate and a long-time software engineer he has been running his own agency and SaaS business before realizing how many people are struggling with cold email outreach. This made him create Mailarrow, the cold email outreach software that helps you build great relationships at scale. Find him on Twitter and LinkedIn

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