Why are ESPs recommending incorrect SPF record configurations?
Michael Ko
Co-founder & CEO, Suped
Published 17 Jul 2025
Updated 17 Aug 2025
8 min read
It can be incredibly frustrating to discover that your email service provider (ESP) is recommending incorrect Sender Policy Framework (SPF) record configurations. As someone deeply involved in email deliverability, I've seen this issue surface repeatedly, leading to confusion and, more critically, to email delivery problems for businesses. The core of the problem lies in a misunderstanding of how SPF works, particularly concerning the different 'From' addresses involved in email sending.
Many ESPs incorrectly advise customers to add an SPF record for their Header-From domain (the one recipients see in their inbox) to their DNS. This is often unnecessary and can cause significant deliverability issues. The SPF check primarily validates the Return-Path (or Mailfrom) domain, which ESPs typically control. When instructions are misaligned with this fundamental principle, businesses end up with improperly configured DNS records, risking their email program.
The primary reason some ESPs provide incorrect SPF guidance stems from a lack of deep technical understanding within certain departments. Often, the teams responsible for writing documentation or providing customer support may not fully grasp the intricacies of email authentication protocols like SPF, DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting, and Conformance (DMARC).
This oversight means that instructions might be copied from older, less accurate templates or generalized to simplify the setup process without considering the specific technical requirements for different types of domains. For example, some ESPs use their own sending domains for the Return-Path, meaning you don't need to add their SPF includes to your main organizational domain. Yet, the documentation still suggests it, leading to redundancy and potential issues.
Another contributing factor is the desire to make the setup process seem easy for non-technical users. While admirable, simplifying complex DNS configurations without technical accuracy often backfires, creating more problems than it solves. This can be especially problematic when dealing with multiple sending providers and their varied recommendations.
The issue
ESPs providing SPF instructions that are unnecessary or incorrect for your organizational domain, especially when they manage the Return-Path themselves. This includes advising users to add include: statements for their service directly to your primary domain's SPF record.
The risks of incorrect SPF recommendations
One of the most immediate dangers of incorrect SPF configurations is exceeding the 10 DNS lookup limit specified by the SPF RFC (RFC 7208 section 4.6.4). Each include, a, mx, and ptr mechanisms can consume a lookup. If you use multiple ESPs, web hosting services, or even Google Workspace, you can quickly hit this limit. Exceeding it results in a PermError, causing receiving mail servers to treat your legitimate emails as unauthenticated or even spam. You can learn more about how SPF resolution fails with CNAME records and other DNS entries if SPF is failing even with an IP in the record.
Beyond lookup limits, incorrect SPF records (or blocklists (blacklists) generally) can lead to serious email deliverability issues. When an email fails SPF authentication, it signals to the receiving server that the email might be forged or sent from an unauthorized source. This significantly increases the likelihood that your emails will be sent to the spam folder or rejected outright, harming your sender reputation and impacting your ability to reach your audience. This can be especially frustrating when coupled with DKIM body hash mismatch failures, or other SPF and DKIM failures.
Another subtle but critical risk is that these misconfigurations perpetuate a flawed understanding of email authentication standards. Businesses might believe they are fully protected, while in reality, their SPF setup is either ineffective or actively causing problems. This can be compounded when organizations are also misadvised to rush towards an enforcing DMARC policy without proper foundational authentication in place, as outlined in common DMARC policy examples. This often results in legitimate emails not reaching the inbox, leading to frustrated customers and lost opportunities.
Correct SPF application
SPF validates the Return-Path domain (Mailfrom or RFC 5321.From), not the Header-From domain (RFC 5322.From) which is what recipients usually see. An ESP typically manages the Return-Path domain, which is often a subdomain of the ESP itself (e.g., bounces.esp.com). This means the SPF record belongs on the ESP's domain, not yours, unless you've configured a custom Return-Path.
Incorrect SPF application
Adding an SPF record (or include statement) to your organizational domain (e.g., yourdomain.com) when the ESP is using their own Return-Path domain. This does not help SPF authentication for your emails and can lead to exceeding the 10-DNS lookup limit on your primary domain's SPF record, causing SPF failures.
Understanding SPF mechanics
To truly understand why ESP recommendations can be misleading, we need to clarify the fundamental SPF mechanics. SPF checks the envelope sender (or Mailfrom, or RFC 5321.From) domain against the SPF record published for that specific domain. Most ESPs handle bounces and other feedback loops by setting the Return-Path to a subdomain they control, such as bounces.your-esp.com. In this scenario, the SPF record is checked against your-esp.com, not your primary domain.
This distinction is crucial. If your ESP is managing the Return-Path domain on your behalf, they are responsible for ensuring SPF is correctly configured for their domain. Adding their include statement to your organizational domain's SPF record (which typically validates your Header-From when DMARC is enforced) becomes redundant and can lead to the 10-lookup limit being exceeded. This is a common pitfall that can lead to SPF authentication issues.
The only time you need to add an SPF record for an ESP to your primary domain is if that ESP explicitly uses your primary domain for the Return-Path (RFC 5321.From). This is less common for marketing and transactional ESPs, which prioritize bounce management and reputation segregation by using their own subdomains. For direct mail servers or certain hosting providers, SPF for your organizational domain may be necessary.
Example of an incorrect SPF recommendation
Here's an example of confusing documentation that implies adding an SPF include for servers.mcsv.net (Mailchimp) to your domain, even though Mailchimp typically uses its own domains for SPF:
SPF record example for new domain
v=spf1 include:servers.mcsv.net -all
Or, if you already have an SPF record, inserting it before the terminating mechanism:
SPF record example for existing domain
v=spf1 a include:servers.mcsv.net -all
This is incorrect because Mailchimp does not allow custom SPF domains; it always uses its own domain for SPF validation. You should generally avoid adding Mailchimp to your SPF record.
Best practices for SPF configuration
To ensure optimal email deliverability, it's crucial to adopt best practices for SPF configuration, especially when using multiple ESPs. One of the most effective strategies is to send email from subdomains. For example, if your primary domain is yourdomain.com, use marketing.yourdomain.com for your marketing ESP and transactional.yourdomain.com for transactional emails. Each subdomain can then have its own dedicated SPF record, ensuring that you stay within the 10-lookup limit for each specific sending stream.
When an ESP provides documentation, cross-reference it with your understanding of SPF. If their instructions suggest adding an include to your organizational domain, confirm whether they are actually using your domain for the Return-Path. In most cases, they aren't, and you can safely skip that step for your main domain. This is particularly relevant when dealing with services like Salesforce or Office 365 where the Return-Path is often managed separately. This can help you avoid problems, especially the SPF DNS timeout at Microsoft.
Regularly audit your domain's DNS records, especially your SPF record, to identify any unnecessary or redundant entries. Tools like an SPF record tester can help you visualize your SPF lookups and ensure you're not exceeding the limit. If you find multiple SPF records or redundant includes for ESPs that handle their own Return-Path, simplify them. This proactive approach helps maintain a clean and effective SPF record, bolstering your email deliverability and ensuring your emails reach their intended recipients.
SPF best practices
Dedicated subdomains: Use separate subdomains for different sending purposes and ESPs. This isolates your sender reputation and simplifies SPF management for each stream.
Understand the From addresses: Always differentiate between the RFC 5321.From (Return-Path, validated by SPF) and RFC 5322.From (Header-From, visible to recipients). Most ESPs use their own domains for the Return-Path.
DNS lookup limits: Monitor and optimize your SPF record to stay within the 10 DNS lookup limit. Exceeding this limit will cause SPF to fail, leading to delivery issues.
Regular audits: Periodically review your SPF record for accuracy and remove any outdated or unnecessary include statements.
Maintaining accurate SPF for optimal deliverability
While the intention of ESPs is often to simplify setup, their occasional incorrect SPF recommendations can paradoxically complicate email deliverability. The key takeaway is to rely on a solid understanding of SPF mechanics rather than blindly following all instructions. Knowing the difference between the Return-Path and Header-From domains, and recognizing when an SPF include is truly necessary, empowers you to maintain optimal email authentication.
Proactive auditing of your DNS records and adherence to best practices, such as using subdomains for different sending streams, will safeguard your sender reputation and ensure your emails consistently land in the inbox. This vigilance is essential for effective email communication and avoiding the pitfalls of misconfigured email authentication.
Views from the trenches
Best practices
Always use distinct subdomains for different email sending purposes or ESPs to compartmentalize reputation.
Understand that SPF primarily authenticates the Return-Path domain, which ESPs often control via their own subdomains.
Regularly review your SPF record to ensure it complies with the 10 DNS lookup limit.
Common pitfalls
Adding an ESP's SPF 'include' to your organizational domain when they use their own Return-Path.
Exceeding the 10 DNS lookup limit due to too many includes or complex records.
Believing a single SPF record should cover all sending from your primary domain, regardless of Return-Path.
Expert tips
Confirm the actual Return-Path domain an ESP uses before adding any SPF includes to your domain.
If an ESP recommends adding their IP address instead of an 'include', consider that as it saves DNS lookups.
Educate clients about the difference between RFC 5321.From and RFC 5322.From to demystify SPF.
Expert view
An expert from Email Geeks says that many email sending companies incorrectly configure SPF for customers. SPF records should not be added for the RFC 5322.From domain.
2021-10-28 - Email Geeks
Marketer view
A marketer from Email Geeks says that incorrect SPF advice clutters the organizational domain's record, often exceeding the 10 DNS lookup limit allowed by RFC 7208. It is tiresome to continually persuade people that SPF is often not needed in the organizational domain.
Google Workspace, you can quickly hit this limit. Exceeding it results in a PermError, causing receiving mail servers to treat your legitimate emails as unauthenticated or even spam. You can learn more about how SPF resolution fails with CNAME records and other DNS entries if SPF is failing even with an IP in the record.
Salesforce or 
Office 365 where the Return-Path is often managed separately. This can help you avoid problems, especially the SPF DNS timeout at Microsoft.
