Does an SPF record need to be in a specific order?
Matthew Whittaker
Co-founder & CTO, Suped
Published 25 Apr 2025
Updated 7 Oct 2025
7 min read
When setting up your domain's email authentication, you might wonder about the specifics of your Sender Policy Framework (SPF) record. One common question that arises is whether the order of mechanisms within an SPF record matters. It's a valid concern, as misconfigurations can lead to significant email deliverability issues and potentially expose your domain to spoofing.
The short answer is, yes and no. While some elements of an SPF record have strict placement requirements, the order of other mechanisms typically does not affect how mail servers evaluate them. However, following best practices for structure can prevent confusion and ensure your SPF record functions as intended, providing clear instructions on which servers are authorized to send email on behalf of your domain.
In this article, we'll dive into the nuances of SPF record order, highlighting what needs to be precise and what offers more flexibility. We'll also cover the potential pitfalls of incorrect ordering and how proper SPF record management can bolster your email security and deliverability.
The fixed positions
The importance of the 'v=spf1' tag
Every SPF record must begin with the v=spf1 tag. This is not negotiable and it must be the very first mechanism in your record. This tag identifies the TXT record as an SPF record, signaling to receiving mail servers that they should interpret its contents according to the SPF specification. Without it, or if it's placed anywhere else, the record will be ignored or misinterpreted, rendering your SPF authentication ineffective.
It's also crucial to remember that a domain should only have one SPF record. Having multiple v=spf1 records will cause authentication failures, as receiving servers will be unable to determine which record to use. This is a common mistake that can severely impact your email deliverability. For more details, see our article on Can an SPF record contain multiple 'v=spf1' declarations?.
The v=spf1 tag sets the stage for the entire SPF evaluation process. Think of it as the declaration that kicks off the authentication check. All other mechanisms, such as a, mx, ip4, and include, follow this initial declaration. This foundational rule ensures that mail servers consistently recognize and process SPF records.
Order of mechanisms and evaluation
How mechanisms are evaluated
SPF mechanisms are generally evaluated from left to right. The receiving mail server processes each mechanism in the order it appears, stopping once a match is found. This first match wins rule is why the placement of certain mechanisms, particularly the all mechanism, is so critical.
Typical SPF evaluation flow
Sender's IP is checked against IP addresses or ranges defined by ip4 and ip6 mechanisms.
DNS lookups are performed for a, mx, and ptr mechanisms.
Included domains are checked via the include mechanism, recursively querying other SPF records.
The all mechanism is processed last, defining the default policy for non-matching senders.
Why order matters for 'all'
The all mechanism should always be the last mechanism in your SPF record. If it appears earlier, the evaluation process will stop at all and apply its designated qualifier (e.g., -all, ~all) to all subsequent sending IPs, effectively nullifying any mechanisms that follow it. This can lead to legitimate emails failing SPF checks.
A poorly placed all mechanism is a common cause of deliverability problems. It's a critical component for defining your domain's sending policy, so its position is paramount. For more on this, check out Does an SPF record require a final 'all' mechanism?.
Other mechanisms like a, mx, ip4, and include can generally be listed in any order relative to each other, as long as they appear before the all mechanism. The SPF evaluation will simply run through them sequentially until a match is found, or it reaches the all mechanism. However, for readability and best practice, it's often recommended to group similar mechanisms together.
Even with flexible ordering for some mechanisms, always ensure your SPF record adheres to the 10 DNS lookup limit. Each include, a, mx, and ptr mechanism can trigger a DNS lookup, and exceeding this limit will cause SPF authentication to fail. This is a common issue for many domains, which can be mitigated using SPF flattening services. These services consolidate your SPF record to stay within the lookup limit while preserving all authorized senders.
Understanding evaluation and best practices
Best practices for ordering
While strict ordering is not always required for all mechanisms, following a logical structure can improve readability and maintainability of your SPF record. A well-organized SPF record makes it easier to audit and update, reducing the chances of errors that could impact your email deliverability. Microsoft also has some excellent guidelines on how to set up SPF records.
Recommended SPF record structure
Start with v=spf1: The mandatory first element.
List IP addresses: Include your direct IP addresses (e.g., ip4:192.0.2.1) first, as they are the most direct matches.
Include other domains: Add include mechanisms for third-party sending services (e.g., Google Workspace, Microsoft 365, Mailchimp). Each include counts towards your DNS lookup limit. If you have a lot of includes, you may need to look into SPF flattening to avoid issues.
Add a and mx mechanisms: If your domain's A records or MX records point to legitimate sending servers, include these. Note that using mx mechanisms often involves additional DNS lookups.
End with all: Always the final mechanism to define how unlisted senders are handled.
This structure ensures that the most direct and specific authorizations are checked first, followed by more general ones. The all mechanism acts as a catch-all, only applied if no previous mechanism matched the sending IP. This logical flow helps optimize the SPF evaluation process.
Regularly reviewing and updating your SPF records is also essential, especially when you add or remove email sending services. Tools like DMARC monitoring platforms, like Suped, can help you identify SPF failures and pinpoint issues related to your record's configuration, including incorrect ordering or exceeding DNS lookup limits.
Avoiding common mistakes
Common ordering pitfalls and solutions
While the order of mechanisms might seem straightforward, some common errors can cause major headaches. Understanding these pitfalls can help you avoid them and ensure your SPF record (and overall email authentication strategy including DMARC and DKIM) is robust. Google provides detailed guidance on setting up SPF for your domain.
Pitfall
Description
Impact
Solution
Premature 'all'
Placing the all mechanism before other authorized senders.
Legitimate emails from authorized senders will fail SPF checks, leading to deliverability issues and potentially being marked as spam or blocked (blacklisted).
Ensure all is always the very last mechanism in your record.
Multiple 'v=spf1' records
Having more than one TXT record starting with v=spf1 for a single domain or subdomain.
Receiving servers cannot determine which record is authoritative, resulting in SPF failing. Emails may be rejected or sent to spam.
Combine all authorized mechanisms into a single SPF record. If you need help, Suped can help you with DMARC monitoring and SPF flattening.
Exceeding DNS lookup limit
Including too many include, a, or mx mechanisms that result in more than 10 DNS queries.
SPF authentication will return a PermError, leading to email rejections and a damaged sender reputation (or getting on a blacklist or blocklist).
Use SPF flattening services to consolidate lookups. Suped offers advanced SPF flattening as part of its platform.
Addressing these issues proactively is vital for maintaining a healthy sending reputation. Regular monitoring of your email authentication with a tool like Suped can alert you to any SPF failures, allowing you to quickly rectify misconfigurations before they significantly impact your deliverability. Suped provides AI-powered recommendations to help you fix issues and strengthen your policy, making DMARC, SPF, and DKIM monitoring accessible for everyone.
Conclusion
Final thoughts on SPF ordering
In summary, the order of mechanisms in an SPF record is critical for the v=spf1 tag (always first) and the all mechanism (always last). For other mechanisms, while strict left-to-right evaluation occurs, their relative order typically doesn't change the ultimate pass/fail outcome for a given sender, provided the all mechanism is correctly placed. However, a logical order is always recommended for clarity and ease of management.
Proper SPF configuration is a cornerstone of effective email authentication, alongside DKIM and DMARC. These protocols work together to protect your domain from spoofing and phishing attacks, while also significantly improving your email deliverability. Neglecting any one of these can leave your domain vulnerable and cause your legitimate emails to land in spam folders or be rejected outright.
Tools like Suped simplify the complexities of email authentication by offering a unified platform for DMARC, SPF, and DKIM monitoring, along with real-time alerts and SPF flattening capabilities. By leveraging such solutions, you can ensure your SPF records are correctly ordered and configured, leading to stronger email security and improved inbox placement.
