Summary
ESPs recommend incorrect SPF configurations due to a complex interplay of factors. Legacy practices, outdated documentation, and the desire for simplified instructions for non-technical users all contribute. This simplification often sacrifices accuracy. Specific issues include incorrect guidance on the 5322.from address, failing to publish SPF records for 5321.from addresses, exceeding DNS lookup limits, and incorrectly instructing customers to include the ESP's domain in their SPF records. Furthermore, some ESPs demonstrate a lack of diligence, failing to update documentation or properly validate configurations. This confusion is exacerbated by the inherent complexities of SPF deployment, particularly when multiple email providers are involved. As a result, misconfigured SPF records can significantly impact deliverability and security.
Key findings
- 5322.from Misconfiguration: Email sending companies frequently misconfigure SPF records related to the 5322.from address.
- 5321.from Record Omission: Companies often fail to publish SPF records for their 5321.from addresses.
- DNS Lookup Limit Exceeded: Incorrect SPF setups lead to exceeding the 10 DNS lookup limit specified in RFC 7208.
- Invalid ESP Includes: ESPs often incorrectly instruct customers to include the ESP's domain in their SPF record.
- Legacy Practices Persist: Outdated documentation and legacy practices continue to promote incorrect SPF configurations.
- Oversimplification Tradeoffs: Efforts to simplify SPF setup for non-technical users often sacrifice accuracy.
- Scope Confusion: Lack of understanding of the distinction between the `MAIL FROM` (5321.MailFrom) and `From:` header addresses leads to misconfigurations.
- SPF Validation Neglected: Validation steps are often overlooked, leading to easily preventable errors.
- Deployment Complexity: The complexity of SPF deployment, especially with multiple providers, contributes to errors.
Key considerations
- Address 5322.from Configuration: Pay close attention to the proper configuration of SPF records related to the 5322.from address.
- Always Publish 5321.from Records: Ensure that SPF records are always published for the 5321.from address.
- Stay Within the DNS Lookup Limit: Take steps to avoid exceeding the 10 DNS lookup limit.
- Avoid Invalid ESP Includes: Do not include the ESP's domain in the organizational SPF record unless you know it is a valid and up-to-date way for them to be sending mail as you.
- Modernize Documentation: Keep documentation and training materials up-to-date.
- Balance Simplicity with Accuracy: Be aware of the tradeoff between simplified configuration and potential inaccuracies.
- Understand SPF Scope Thoroughly: Fully understand the scope of SPF and its relationship to the `MAIL FROM` address.
- Implement Validation Practices: Establish procedures for validating SPF records to catch errors early.
- Validate SPF Records: Validate and check your SPF records after creation
- Seek Professional Guidance: Don't hesitate to seek guidance from experts
What email marketers say
11 marketer opinions
ESPs sometimes recommend incorrect SPF configurations due to a combination of factors, including legacy practices, oversimplified instructions for non-technical users, and outdated documentation. Some ESPs prioritize ease of implementation and reducing support requests over technical accuracy. This can lead to exceeding DNS lookup limits, publishing invalid SPF records, and potentially allowing malicious emails to appear legitimate. A lack of expertise and time commitment to updating documentation also contribute to the problem. Misunderstandings arise when clients have multiple mail providers and improperly add the SPF records.
Key opinions
- Legacy Practices: Outdated documentation and legacy practices within ESPs contribute to incorrect SPF recommendations.
- Oversimplification: ESPs often oversimplify SPF setup instructions for non-technical users, sacrificing accuracy for ease of implementation.
- Resource Constraints: Some ESPs are unwilling to invest the time and resources needed to maintain accurate and up-to-date documentation.
- DNS Lookup Limits: Incorrect SPF configurations frequently lead to exceeding the 10 DNS lookup limit, causing SPF checks to fail.
- Multiple Providers: Confusion arises when clients have multiple email providers and fail to properly configure their SPF records.
Key considerations
- Accuracy vs. Simplicity: ESPs must balance the need for simplified instructions with the importance of technical accuracy in SPF record configurations.
- Documentation Updates: ESPs should prioritize regularly updating their documentation to reflect current best practices for SPF records.
- Technical Expertise: Clients should seek expert advice to ensure their SPF records are correctly configured, especially when using multiple email providers.
- Impact of Errors: Incorrect SPF configurations can negatively impact email deliverability and potentially expose domains to security risks.
- Validating SPF: Ensure you validate your SPF record once you have created it, as this is the best way to ensure that it is setup correctly.
Marketer view
Email marketer from Stack Overflow explains that some shared hosting providers recommend customers include the hosting provider's domain in their SPF record, but this can potentially allow malicious emails to be sent from that shared host, and make them seem valid.
13 Jun 2025 - Stack Overflow
Marketer view
Email marketer from MailerCheck suggests that some ESPs may recommend technically incorrect SPF configurations due to laziness, or not wanting to fully invest the time to provide customers with the correct instructions.
28 Oct 2022 - MailerCheck
What the experts say
7 expert opinions
ESPs often recommend incorrect SPF configurations due to flawed documentation, legacy practices, and a fundamental misunderstanding of SPF implementation. This results in companies not publishing SPF records correctly and exceeding DNS lookup limits. Common errors include instructing customers to include the ESP's domain in the customer's SPF record (which is invalid) and recommending incorrect `include` statements, leading to deployment problems and broken email deliverability.
Key opinions
- Frequency of Errors: Email sending companies frequently misconfigure SPF records, particularly concerning the 5322.from address.
- DNS Lookup Limit Exceeded: Incorrect configurations lead to companies not publishing SPF records for their 5321.from addresses and exceeding the 10 DNS lookup limit.
- Incorrect Includes: ESPs incorrectly instruct customers to include their domain in the SPF record or provide specific IP addresses inappropriately.
- 5321 vs 5322 confusion: ESPs set up subdomains on the 5322.from but instruct customers to publish an include: in their 5321.from domain, which is not valid SPF.
- Deployment Problems: SPF deployment is complex, leading to too many lookups and broken deliverability.
Key considerations
- Documentation Accuracy: ESPs should ensure their documentation provides accurate and up-to-date instructions for SPF configuration.
- Understanding SPF Scope: It's crucial to understand the difference between 5321.from and 5322.from addresses and configure SPF records accordingly.
- Lookup Limit Awareness: Be mindful of the DNS lookup limit and avoid exceeding it by optimizing SPF records and using IP addresses where appropriate.
- Validating SPF Records: Validate SPF records to ensure they are correctly configured and don't contain errors.
- Expert Assistance: Seek expert assistance to navigate the complexities of SPF deployment and ensure optimal deliverability.
Expert view
Expert from Email Geeks shares an example where an ESP instructs users to add include:email.influitive.com to their SPF record or use a specific IP address, warning about SPF lookup limits.
15 Feb 2024 - Email Geeks
Expert view
Expert from Email Geeks explains that incorrect SPF configurations lead to companies not publishing SPF records for their 5321.from addresses and exceeding the 10 DNS lookup limit.
3 Sep 2021 - Email Geeks
What the documentation says
6 technical articles
ESPs recommending incorrect SPF configurations often result in issues related to DNS lookup limits, improper SPF scope understanding, and syntax errors. RFC 7208 specifies a 10 DNS lookup limit, which is often exceeded due to nested `include` mechanisms. Additionally, confusion arises from blurring the distinction between the `MAIL FROM` address and the `From:` header. Incorrect syntax can lead to authentication failures, and failure to use the correct domain decreases deliverability. Validation is crucial to avoid phishing scams.
Key findings
- DNS Lookup Limit: RFC 7208 specifies a 10 DNS lookup limit for SPF records; incorrect configurations often exceed this limit.
- Improper SPF Scope: SPF applies only to the `MAIL FROM` address (5321.MailFrom), not the `From:` header address.
- Nested Lookups: SPF records using `include` mechanisms can lead to multiple nested DNS lookups, exceeding the limit.
- Syntax Errors: Improper syntax in SPF records can cause authentication failures and impact deliverability.
- Correct Domain: It's important to use the correct domain for your mail sending in your SPF record.
Key considerations
- Adherence to RFC 7208: Ensure SPF records adhere to the 10 DNS lookup limit specified in RFC 7208.
- SPF Scope Awareness: Understand the scope of SPF and its application to the `MAIL FROM` address.
- Lookup Optimization: Minimize nested DNS lookups by optimizing the use of `include` mechanisms.
- Syntax Validation: Validate SPF record syntax to prevent authentication failures.
- SPF Validation: Always validate SPF records to prevent configuration issues that can lead to phishing attempts.
Technical article
Documentation from datatracker.ietf.org explains that the RFC 7208 specifies a limit of 10 DNS lookups for SPF records. Incorrect configurations often lead to exceeding this limit, which can cause SPF checks to fail.
13 Sep 2021 - datatracker.ietf.org
Technical article
Documentation from Google shares the importance of making sure you are using the correct domain for your mail sending in your SPF record, and if you fail to do this your mail is less likely to get delivered, as Google and other providers will correctly mark the email as spam or a threat.
3 Jun 2024 - Google Workspace Admin Help
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