SPF Setup for Mailgun

December 14, 2025 • InboxGreenEmail Team

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Setting up SPF for Mailgun can feel daunting, especially if you are not familiar with email authentication protocols. However, getting it right is crucial for ensuring your emails land in the inbox, not the spam folder. A poorly configured SPF record can lead to bounced emails, warnings in Gmail, or worse, your domain getting flagged for spam. This is urgent, especially if you notice a drop in engagement or if your emails are not being delivered at all. Let's break down the steps to get your SPF record configured correctly with Mailgun.

At a glance

This problem affects SaaS founders, marketers, and technical teams managing email sending.
This article will help you set up SPF for Mailgun effectively.
By following these steps, you will improve your inbox placement and domain reputation.

When this problem shows up in real life

Imagine you send out an important marketing email to your subscribers, only to find out later that a significant portion of them never received it. You check your logs and see error messages like:

550 5.7.1 Message rejected due to SPF failure

Or perhaps you notice in Gmail headers:

Authentication-Results: mx.google.com; spf=fail (google.com: domain of example.com does not designate 192.0.2.1 as permitted sender)

These messages indicate that your SPF record is not set up correctly, causing your emails to be rejected or sent to spam. You may also receive support tickets from users reporting that they did not receive your emails, which can be frustrating and damaging to your reputation.

Step by step: SPF setup for Mailgun

Log into your DNS provider.
Access the DNS management console for the domain you are sending emails from. This could be your domain registrar or hosting provider.
Locate your SPF record.
Check if you already have an SPF record. It will look something like this:
```
v=spf1 include:mailgun.org ~all
```
If it does not exist, you will need to create one.
Create or update your SPF record.
If you are using Mailgun, your SPF record should include Mailgun's servers. Here’s how to do it:
```
v=spf1 include:mailgun.org -all
```
This record tells receiving servers to accept emails sent from Mailgun on behalf of your domain.
Save your changes.
After adding or updating your SPF record, make sure to save your changes. DNS changes can take some time to propagate, so be patient.
Verify your SPF record.
Use the SPF generator to ensure your record is correct. You can also check it with the InboxGreen checker to confirm it is set up properly.

Common mistakes

Missing SPF record.
Symptom: Emails are bouncing back with SPF errors.

Cause: No SPF record exists for your domain.

Fix: Create an SPF record as shown above.
Incorrect SPF syntax.
Symptom: SPF validation fails.

Cause: Typos or incorrect formatting in the SPF record.

Fix: Double-check the syntax and use the SPF generator for accuracy.
Using multiple SPF records.
Symptom: SPF fails with a "too many DNS lookups" error.

Cause: Having more than one SPF record for a domain.

Fix: Combine all mechanisms into a single SPF record.
Not including all sending services.
Symptom: Some emails are still going to spam.

Cause: Missing includes for other services you use.

Fix: Make sure to include all relevant services in your SPF record.

Troubleshooting when it still fails

SPF record looks correct → Emails still fail.
Likely cause: DNS propagation delay. Changes can take time to reflect.

What to try next: Wait a few hours, then check again.
Authentication-Results shows SPF fail → No clear errors.
Likely cause: The sending IP is not listed in the SPF record.

What to try next: Verify the sending IP and update the SPF record accordingly.
SPF record is valid → Emails still in spam.
Likely cause: Other factors affecting reputation, like engagement rates.

What to try next: Check your domain reputation and engagement metrics.

Related checks you should run

Ensure SPF, DKIM, and DMARC are aligned for your domain.
Check DNS TTL settings and propagation delays.
Review your domain reputation and monitor for bounces or spam reports.
Evaluate your email list quality and engagement patterns.

FAQ

Why is SPF still failing on Mailgun after I added the record?

If SPF is still failing, it could be due to DNS propagation delays. It can take some time for changes to take effect. Use the InboxGreen checker to verify if the record is visible.

How long do DNS changes take to apply on Mailgun?

DNS changes can take anywhere from a few minutes to 48 hours to propagate, depending on the TTL settings of your DNS records.

Can I use more than one SPF include with this setup?

Yes, you can include multiple services in your SPF record. Just make sure to stay within the limit of 10 DNS lookups to avoid errors.

What should I do if my emails are still going to spam?

Check your domain's reputation, engagement metrics, and ensure that DKIM and DMARC are also set up correctly. Use tools like the InboxGreen checker for a comprehensive analysis.

How can I verify my SPF record is correctly set up?

You can use the SPF generator to create a record and then verify it with the InboxGreen checker to ensure everything is correct.

What to do next

Now that you have set up your SPF record for Mailgun, it is important to regularly check its status. Use the InboxGreen checker to monitor your email authentication records and ensure they are functioning as intended. This proactive approach will help maintain your domain's reputation and improve inbox placement. Don't forget to also check your DKIM and DMARC settings for a complete email authentication strategy.

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