What is SPF for Email? Email Marketing Authentication Frameworks

What is SPF for Email
Josh M
Author: J. Michaels
Mateo B
Reviewed by: Mateo Beltroy
What is SPF for Email

The Sender Policy Framework (SPF) is a standard designed to authenticate email messages and shield against practices like spoofing and phishing. Our exploration focuses on understanding SPF’s integral role in email security, its operational mechanics, and the benefits it contributes to protecting email marketing communications.

How Does SPF Work?

When it comes to email security, Sender Policy Framework (SPF) acts almost as a frontline defense. Originating as an email authentication protocol, SPF allows domain owners to specify which email servers are authorized to send emails on their behalf. This authentication is important for preventing the forgery of sender information in emails – a common tactic used in spam and phishing attacks.

Essentially, SPF works by enabling email receivers to verify if an incoming email originates from a listed, authorized server, or not. If an email claims to come from a particular domain, but the sending server isn’t recognized in the SPF record, it’s flagged as unverified, thereby alerting the receiver to potential fraud or spam. This system of verification ensures that only emails from legitimate sources reach their intended recipients.

The implementation of SPF is straightforward yet powerful. It involves creating a TXT record in the DNS that outlines the approved sending sources. This record is then used by receiving mail servers to check the authenticity of incoming messages.

SPF Explained

What Does an SPF Email Record Look Like?

An SPF record, encoded as a TXT record in the DNS, is not just a list but a set of instructions that guide the email validation process. Here’s a closer look at its components with examples:

  • SPF Version: Each record begins with v=spf1, indicating the SPF protocol version being used.
  • Mechanisms: These define which hosts are allowed to send mail from the domain. Common mechanisms include:
    • a – Refers to the domain’s A records; emails sent from IPs matching these records are authorized.
    • mx – Allows emails from IPs listed in the domain’s MX records.
    • ip4 and ip6 – Specify authorized IPv4 and IPv6 addresses, respectively.
    • include – Incorporates the SPF record of another domain, useful for third-party email services.

Example SPF Record:

v=spf1 ip4: include:_spf.google.com ~all

In this example:

  • ip4: allows emails from the IP address
  • include:_spf.google.com permits emails from Google’s servers.
  • ~all indicates a soft fail for emails from IPs not listed, suggesting they be treated with suspicion but not outright rejected.
  • Modifiers: Additional directives like redirect can modify how SPF processes the record.

Advanced Example:

v=spf1 a mx include:mailservers.com ip4: -all

This SPF record:

  • Approves emails from the domain’s A and MX record IPs.
  • Includes mailservers.com’s SPF.
  • Specifically authorizes the IP
  • Ends with -all, denoting a hard fail for unlisted IPs, recommending their outright rejection.

The SPF record’s composition is crucial in determining email legitimacy. A well-structured SPF can effectively minimize the risks of email spoofing, improving a domain’s email security position.

  • Approves emails from the domain’s A and MX record IPs.
  • Includes mailservers.com’s SPF.
  • Specifically authorizes the IP
  • Ends with -all, denoting a hard fail for unlisted IPs, recommending their outright rejection.

The SPF record’s composition is crucial in determining email legitimacy. A well-structured SPF can effectively minimize the risks of email spoofing, improving a domain’s email security position.

The Role of SPF in Preventing Email Fraud

SPF is important in the fight against email fraud, particularly spoofing and phishing. By verifying if an email comes from an authorized server, SPF can significantly reduce unauthorized use of a domain for sending fraudulent emails. This is especially important since email spoofing is often used in phishing attacks, where attackers disguise themselves as legitimate entities to deceive recipients.

When an SPF check fails (indicating an email is from an unauthorized server), the receiving server can flag the email, alerting recipients to potential fraud. This not only helps protect end-users from deceptive emails but also maintains the integrity and reputation of the domain used by the sender.

Basically, SPF helps protect domain reputation, signaling to email recipients and servers alike that a domain is actively managed and secured against email-based threats.

By enforcing email authenticity, SPF plays a crucial role in overall email security strategy, contributing to a safer, more trustworthy digital communication.

SPF is even more important when it comes to email marketing strategies as the domain owner is likely sending out thousands of emails to recipients about their products and services. If the domain reputation is harmed, they may not be able to send emails to their audience, or the audience may receive a warning about the email being spam or fraudulent.

Setting Up an SPF Record: A Step-by-Step Guide for Beginners

Creating an SPF record might seem technical, but it’s quite manageable with a step-by-step approach:

Step 1: Gather Information

  • Identify Email Servers: List all the sources that send emails on your behalf. This includes your own email server and any third-party email services you use (like Google Workspace or MailChimp).

Step 2: Construct Your SPF Record

  • Start with the Version Tag: Every SPF record begins with v=spf1. This tells the receiving email server that your record follows SPF’s first version.
  • Add Your Sending Sources:
    • Use ip4: or ip6: for specific IP addresses. For example, ip4: tells that this particular IP address is authorized.
    • Use include: for third-party servers. For instance, include:thirdpartyservice.com means emails sent from this service are legitimate.
    • The a and mx tags automatically authorize your domain’s A records (web servers) and MX records (mail servers), respectively.

Step 3: Finalize and Add the Record

  • Choose a Policy for Unmatched Emails: End your record with a policy like ~all (soft fail) or -all (hard fail). ~all is more forgiving, marking unmatched emails as suspicious but not outright rejecting them.
  • Combine the Elements: Your final record might look like v=spf1 ip4: include:thirdpartyservice.com ~all.

Step 4: Publish the SPF Record in DNS

  • Log into the control panel where your domain’s DNS is managed.
  • Create a new TXT record and enter your SPF string into the value field.

Step 5: Test and Verify

  • There are free online tools where you can enter your domain to check if your SPF record is valid and working. For example, use EasyDMARC’s SPF record validator to check your SPF record.

Step 6: Regular Maintenance

  • If you change email services or server IPs, update your SPF record accordingly.

By following these steps, you can set up an SPF record to protect your domain from email spoofing and improve your email delivery rates. Keep in mind that some email servers will provide you with a pre-made SPF record that you can simply copy and paste into your DNS records to set up. Keep an eye out for that as it will make it easier to create the record and avoid any mistakes. Always verify your SPF record with a tool to make sure it is working properly.

SPF Mechanisms and Qualifiers

Understanding SPF mechanisms and qualifiers is crucial for effective email authentication. Here’s a breakdown:


  • a and mx: Authorizes sending from IPs associated with your domain’s A or MX records.
  • ip4 and ip6: Specifies individual IPv4 or IPv6 addresses allowed to send emails.
  • include: Incorporates SPF records from other domains, useful for third-party email services.


  • + (Pass): The default qualifier, indicating the server is authorized.
  • – (Fail): Directs that emails from the server should be rejected.
  • ~ (SoftFail): Marks emails as suspicious but doesn’t outright reject them.
  • ? (Neutral): Indicates no specific policy, often treated as acceptable.

Practical Examples

  • Allows emails from servers listed in the domain’s A and MX records.
    • Soft fails anything else.
    • Third-Party Services: v=spf1 include:_spf.google.com ~all
    • Includes Google’s SPF record, authorizing emails sent through Google services.
    • Soft fails all other sources.

By carefully selecting mechanisms and qualifiers, you can tailor your SPF record to match your specific email sending practices, ensuring a secure and reliable email delivery process.

Email Marketing Validation

The implementation of SPF (Sender Policy Framework) is more than a technical necessity in today’s email marketing landscape; it’s a proactive measure towards a secure and trustworthy email environment.

SPF’s role in authenticating email origins safeguards both senders and recipients from prevalent cyber threats like spoofing and phishing. When combined with DKIM, DMARC, and proper email hygiene, it forms a strong combination in email security. Understanding and effectively deploying SPF not only enhances your domain’s integrity but also contributes to the broader fight against email-based fraud, making our digital interactions safer and more reliable.

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