Understanding whether your Sender Policy Framework (SPF) setup in Marketo is correctly configured can be a source of confusion. I've heard from many marketers who've received notifications from Marketo support about SPF issues, only to find their setup appears correct when checked independently. This often leads to frustration and questions about where the disconnect lies.
The key to resolving these discrepancies is knowing how to validate your SPF record yourself. This way, you can cross-reference Marketo's reports with your own findings and pinpoint any real issues, or confidently demonstrate that your setup is indeed robust. It's about empowering yourself with the knowledge to maintain strong email deliverability.
SPF is a critical email authentication protocol designed to prevent email spoofing. It allows domain owners to publish a DNS TXT record that lists the mail servers authorized to send email on behalf of their domain. When an email server receives an incoming message, it checks the SPF record of the sending domain (specifically the Return-Path domain) to confirm that the sending IP address is authorized. If the check fails, the email might be marked as spam or rejected outright.
For Marketo users, the standard practice is to include include:mktomail.com in your SPF record. This tells recipient mail servers that Marketo's sending infrastructure is permitted to send emails for your domain. It’s a fundamental step in ensuring your emails reach their intended recipients and avoid being flagged by spam filters.
While SPF is essential, it's just one part of a comprehensive email authentication strategy. For optimal deliverability, you should also ensure proper DKIM and DMARC setup. These protocols work together to provide stronger validation of your email's legitimacy, protecting your domain's reputation and improving inbox placement. Without them, even a perfectly configured SPF record might not be enough to guarantee delivery.
It's important to differentiate between shared IP addresses and dedicated IP addresses within Marketo. If you use a shared IP, Marketo often handles much of the SPF authentication through its own mktomail.com domain. However, for a dedicated IP, your SPF record must explicitly declare Marketo's infrastructure as an authorized sender to ensure proper alignment. Understanding this distinction is crucial for accurate validation.
How to validate your SPF record
The most reliable way to validate your Marketo SPF setup is to use an external SPF checker tool. These tools perform a DNS lookup on your domain and analyze your SPF record for syntax errors, common pitfalls, and correct inclusion of authorized sending sources. They will also verify if the IP addresses sending your emails are covered by your SPF record.
A common mistake when validating Marketo SPF is to send a test email directly from Marketo's interface and then check its headers. For some Marketo instances, these test emails might not authenticate against your specific setup, but instead use Marketo's default mktomail.com domain for SPF. This can give a false positive, showing SPF as correctly aligned even if your custom setup has issues.
To get an accurate validation of your Marketo SPF, send a live email campaign or a regular email from a program that uses your configured sending domain. This ensures the email is sent through your actual setup, allowing the SPF checker to verify the correct Return-Path domain and associated IP addresses. You can learn more about Marketo's recommended setup on Adobe's Experience League.
Your SPF record is a TXT record in your DNS. It typically starts with v=spf1 and includes mechanisms like include:, ip4:, and a qualifier such as ~all or -all. It's crucial to have only one SPF TXT record per domain to avoid validation issues. Merging multiple records into one is a common requirement.
After sending a live email, copy the raw email headers and paste them into an email authentication checker. This tool will analyze the Authentication-Results header, which explicitly states whether SPF passed, failed, or encountered a softfail, and if it was aligned with your From: address. This is the definitive way to see how receiving mail servers interpret your SPF setup.
Example SPF record for MarketoDNS
v=spf1 include:mktomail.com ~all
Common Marketo SPF validation challenges
One of the most frequent issues encountered during SPF validation in Marketo, especially for those with a dedicated IP address, is the confusion around whether the SPF record explicitly declares the Marketo sending IP. As discussed, Marketo's test emails may sometimes authenticate under mktomail.com, even if your dedicated IP setup is intended to use your domain's SPF. This can lead to Marketo support incorrectly flagging your setup.
Another challenge is the DNS lookup limit (max 10 lookups) for SPF records. If your SPF record includes multiple include statements for various services in addition to Marketo, you might exceed this limit. When this happens, mail servers will return a PermError, causing your emails to fail SPF authentication and likely land in spam. This issue requires careful consolidation or SPF flattening.
Always remember that SPF validation specifically looks at the Return-Path (or Envelope-From) domain, not the From: header that users see in their inbox. This distinction is vital for accurate troubleshooting. If SPF is failing, you might also be experiencing broader deliverability issues that need addressing. You can find more discussions on SPF and DKIM settings within the Marketo Nation forum.
Views from the trenches
Views from the trenches
Best practices
Ensure your SPF record includes all legitimate sending sources, not just Marketo.
Always test SPF using a live email send, not Marketo's internal test email feature.
Verify that your SPF record adheres to the 10-DNS-lookup limit.
Common pitfalls
Sending test emails from Marketo that don't reflect your actual SPF setup.
Having multiple SPF records for a single domain, leading to PermErrors.
Forgetting that SPF authenticates the Return-Path, not the From: header domain.
Expert tips
Consider SPF flattening services if you have many include mechanisms.
Implement DMARC with a p=none policy to gain visibility into SPF failures.
Work with your DNS provider to ensure record changes propagate correctly.
Expert view
Expert from Email Geeks says: The mail sent from the provided test result page is validated perfectly. For SPF, it is using the envelope domain in the return path, which is valid for the IP address it is being sent from. This domain includes the Marketo customer SPF record, making it valid for any mail sent from there. This setup is absolutely fine.
2024-02-01 - Email Geeks
Marketer view
Marketer from Email Geeks says: My confusion was that the SPF record for the email domain did not explicitly declare mktomail.com. This is not usually an issue for shared IPs, but I thought dedicated IPs needed this declaration. However, the SPF is still authenticating, which clarified that even without an explicit declaration for dedicated IPs, the setup can still authenticate.
2024-02-01 - Email Geeks
Final thoughts on Marketo SPF validation
Validating your SPF setup in Marketo is a crucial step for ensuring email deliverability and maintaining your sender reputation. By understanding how SPF works, particularly with Marketo's specific configurations (like mktomail.com), and using reliable external tools with live email sends, you can confidently verify your authentication.
Don't let conflicting information from support teams derail your efforts. Armed with the right knowledge and tools, you can ensure your Marketo emails are properly authenticated, helping them land in the inbox and achieve better campaign performance. Remember to also keep an eye on your blocklist status and overall email deliverability metrics for a holistic view of your sending health.
