Introduction
Email authentication and spam filtering decide whether your emails reach the inbox or end up in spam. Mailbox providers rely on trust signals to verify every message, and one of the most important is the SPF record in DNS. When SPF is missing or incorrectly configured, receiving servers can’t confirm that your email is coming from an authorized source. This often leads to spam filtering or email rejection. A properly set SPF record DNS tells mail servers which systems are allowed to send emails for your domain, helping prevent spoofing and phishing attacks. In this guide, you’ll learn how SPF works, how to set it up correctly, and how to avoid common mistakes.
Key Takeaways
- SPF record DNS tells mailbox providers which servers are allowed to send emails for your domain
- Missing or incorrect SPF records can cause emails to land in spam or get rejected
- Always publish SPF as a single TXT record and keep DNS lookups under the 10-limit
- Avoid risky settings like +all; use ~all for testing and -all for production
- SPF alone is not enough, combine it with DKIM and DMARC for best results
- Regularly verify and audit your SPF record to maintain sender reputation
Table of Contents
- Introduction
- What Is an SPF Record in DNS?
- How SPF Record DNS Works
- SPF Record Syntax Explained (With Examples)
- How to Create an SPF Record in DNS
- How to Check and Verify Your SPF Record
- Common SPF Record DNS Errors & Fixes
- SPF vs DKIM vs DMARC: What’s the Difference?
- Does SPF Record DNS Affect Inbox Placement?
- Troubleshooting SPF Record DNS Issues
- Conclusion
What Is an SPF Record in DNS?
SPF (Sender Policy Framework) is an email authentication method that helps receiving mail servers verify whether an email is sent from an authorized source. An SPF record is published in your domain’s DNS and lists the mail servers that are allowed to send emails on your behalf.
When you send an email, the receiving server checks your domain’s DNS to find the SPF record and confirms whether the sending IP address is permitted. If it matches, the email passes SPF verification. If not, the email can be rejected or labeled as spam.
Unlike other DNS records that handle website traffic or domain routing, the SPF record focuses specifically on email authorization. Mailbox providers rely on SPF verification to block spoofed emails, reduce phishing attempts, and protect users from fraudulent messages.
How SPF Record DNS Works
When you send an email, it travels from your sending server to the recipient’s mail server along with the sending IP address. Before delivering the message, the receiving server checks your domain’s DNS to find the SPF record.
The SPF record lists which servers are allowed to send emails for your domain. The receiving server compares the sending IP with this list and decides the result:
- Pass – authorized server, email is trusted
- Fail – unauthorized server, email may be rejected
- Softfail (~all) – suspicious but not blocked
- Neutral (?all) – no clear policy
For example, if your SPF allows Google servers and you send from Google Workspace, SPF passes. If someone spoofs your domain from another server, SPF fails and helps block the email.
SPF Record Syntax Explained
An SPF record is published in DNS as a TXT record and follows a simple structure. It always begins with a version identifier, followed by mechanisms that define which servers are allowed to send emails for the domain, and ends with a rule that tells receiving servers how to handle unauthorized senders.
The basic SPF record format looks like this: v=spf1 [mechanisms] [policy]
The v=spf1 tag identifies the record as an SPF record and must always appear at the beginning. Without this tag, mailbox providers will ignore the record completely.
The ip4 and ip6 mechanisms are used to authorize specific IPv4 or IPv6 addresses. These are commonly used when you operate your own mail server and want to allow only certain IPs to send emails on behalf of your domain.
The include mechanism allows third-party email services to send emails for your domain by referencing their SPF records. This is commonly used for services like Google Workspace, Microsoft 365, transactional SMTP providers, and marketing platforms.
The a mechanism allows the IP address associated with the domain’s A record to send emails, while the mx mechanism allows the IP addresses listed in the domain’s MX records. These are useful when mail is handled directly by the same server that hosts your domain or receives emails.
The all mechanism defines what should happen when an email is sent from a server that is not listed in the SPF record. Using -all tells receiving servers to reject unauthorized emails, ~all marks them as suspicious but does not block them, and ?all applies a neutral policy and provides no clear guidance. In most production environments, -all is recommended once testing is complete.
How to Create an SPF Record in DNS
Creating an SPF record is a simple but important step to protect your domain and improve email deliverability. First, list all the services that send emails using your domain, such as your website server, Google Workspace, Microsoft 365, or any SMTP provider.
Next, build your SPF record starting with v=spf1, add the allowed sources, and end with -all or ~all if you are still testing. Then log in to the DNS hosting panel where your domain’s nameservers are managed and add a new TXT record. Paste your SPF record as the value and save it.
Always publish SPF as a TXT record, not as an SPF-type record, and make sure only one SPF record exists for your domain. For TTL, 300–3600 seconds is recommended for most setups.
How to Check and Verify Your SPF Record
Once your SPF record is added, it’s important to verify that it’s working correctly. A small issue can cause emails to fail authentication, even if the record exists.
Check SPF record using DNS lookup
You can check your SPF record directly from DNS by running a lookup. This shows whether your SPF record is published and visible. If the TXT record appears and starts with v=spf1, your SPF record is active. If nothing shows up, DNS may not have propagated yet or the record was added in the wrong place.
Using online SPF record checker tools
Online SPF checker tools make verification easier. Just enter your domain, and the tool will show your SPF record, validate its syntax, and warn you about common issues like multiple SPF records or lookup limit problems.
How to confirm SPF pass status
The best way to confirm SPF is passing is by checking email headers of a delivered message. Look for SPF=pass in the authentication results. This confirms that the sending server is authorized by your SPF record.
What to do if SPF is not validating
If SPF fails, check for multiple SPF records, syntax errors, missing includes, or too many DNS lookups. Fix the issue, update the record, and recheck after DNS propagation.
Common SPF Record DNS Errors & Fixes
Even a small SPF mistake can break email authentication. Below are the most common SPF record DNS errors and how to fix them.
Multiple SPF records in DNS
Having more than one SPF record causes SPF checks to fail. Mail servers stop processing after the first record and ignore the rest.
Fix: Merge all allowed sending sources into one single SPF TXT record.
Exceeding the 10 DNS lookup limit
SPF allows a maximum of 10 DNS lookups. Too many include, a, or mx mechanisms can exceed this limit, causing SPF to fail.
Fix: Remove unnecessary includes, flatten SPF records, or consolidate providers.
Missing include mechanisms
If an email service provider is not listed in your SPF record, emails sent through that service will fail SPF.
Fix: Add the correct include value provided by your email or SMTP service.
Incorrect all qualifier
Using the wrong all policy can either block valid emails or weaken protection.
Fix: Use ~all during testing and switch to -all once your setup is stable.
Syntax errors and typos
Extra spaces, missing colons, or incorrect keywords can invalidate the entire SPF record.
Fix: Double-check formatting and validate the record using an SPF checker tool.
SPF vs DKIM vs DMARC: What’s the Difference?
SPF (Sender Policy Framework) verifies whether the server sending an email is authorized to send mail for a specific domain. It works by checking the sending IP address against the list of approved servers published in the domain’s DNS. SPF helps prevent basic spoofing but does not protect the email content itself.
DKIM (DomainKeys Identified Mail) adds a digital signature to each outgoing email. This signature allows receiving servers to confirm that the message has not been modified in transit and that it genuinely came from the claimed domain. DKIM strengthens trust by protecting message integrity.
DMARC (Domain-based Message Authentication, Reporting & Conformance) enforces the results of SPF and DKIM by telling mailbox providers how to handle emails that fail authentication. It tells mailbox providers how to handle emails that fail authentication and provides reporting for visibility. Together, SPF, DKIM, and DMARC form a complete email authentication system.
Does SPF Record DNS Affect Inbox Placement?
Mailbox providers use SPF as an important trust signal to verify whether an email is sent from an authorized server. When SPF passes, it helps confirm the sender’s identity and supports inbox placement.
If SPF fails, emails are more likely to be filtered as spam or rejected, especially when other checks also fail. Repeated SPF failures can damage domain reputation over time.
SPF alignment—where the sending domain matches the “From” domain—builds sender trust. While SPF alone doesn’t guarantee inbox placement, it plays a key role in maintaining a healthy sending reputation when combined with DKIM and DMARC.
Troubleshooting SPF Record DNS Issues
If emails still go to spam despite SPF passing, it usually means other factors like DKIM, DMARC, sender reputation, or low engagement are affecting deliverability. SPF helps verify the sender but does not guarantee inbox placement on its own.
When SPF passes but DMARC fails, the issue is often domain alignment. The domain authenticated by SPF must match the “From” domain. Fixing alignment or enabling DKIM usually resolves this problem.
For shared IPs or third-party senders, SPF can fail if the provider is not correctly included in your SPF record. Always use the official include value and avoid unnecessary entries.
Forwarded emails may fail SPF because the forwarding server is not authorized. In these cases, DKIM and DMARC are essential to maintain email trust and delivery.
Conclusion
Setting up the SPF record DNS correctly is a foundational step for protecting your domain and improving email deliverability. A well-configured SPF record helps mailbox providers verify your sending servers, reduce spam filtering, and prevent domain spoofing. However, SPF works best when combined with DKIM and DMARC for full authentication and policy enforcement. By following best practices, avoiding common errors, and regularly verifying your SPF setup, you can build long-term sender trust and ensure your emails consistently reach the inbox.
FAQ
No, a domain must have only one SPF record; multiple SPF records cause SPF validation to fail.
No, SPF helps verify the sender but works best when combined with DKIM, DMARC, and good sending practices.
SPF changes usually propagate within minutes but may take up to 24 hours depending on DNS caching and TTL.
Oh! Still not using our email marketing service? Try Now!
Our Plans:-Yearly Email Marketing Plans and Monthly Email Marketing Plans.
FAQ:- (Click Here)Contact our client care for additional Help
