What is universal SPF and how does it help fix broken SPF policies?
Matthew Whittaker
Co-founder & CTO, Suped
Published 28 Apr 2025
Updated 16 Aug 2025
7 min read
Sender Policy Framework (SPF) is a fundamental email authentication standard designed to prevent email spoofing. It allows domain owners to publish a list of authorized mail servers that are permitted to send emails on behalf of their domain. Receiving mail servers then check the SPF record of the sender's domain to verify that the email originated from an approved source. If the sender's IP address isn't listed, the email might be flagged as suspicious, or even rejected, impacting your email deliverability.
While essential, SPF records are notoriously difficult to manage, especially for organizations using multiple third-party email services. The main challenge arises from a technical limitation: the SPF specification (RFC 7208) imposes a 10 DNS lookup limit. Each include mechanism in your SPF record counts towards this limit. Exceeding it results in a PermError, effectively breaking your SPF policy and potentially causing legitimate emails to fail authentication.
This is where universal SPF comes in, offering a clever solution to this persistent problem. It acts as an abstraction layer, simplifying SPF management and ensuring your policies remain compliant and effective, even with complex sending infrastructures. Let's explore how universal SPF addresses these challenges and helps maintain robust email authentication.
The primary pain point for many organizations is the SPF 10-DNS lookup limit. Each time your SPF record includes another domain's SPF record, or a DNS A or MX record is referenced, it consumes one of those precious ten lookups. For businesses using various email service providers (ESPs), CRMs, or marketing automation platforms, this limit is quickly hit, leading to SPF failure.
When your SPF record exceeds this DNS lookup limit, it triggers an SPF PermError. This error signals to receiving mail servers that your SPF policy is invalid. Unlike a SoftFail or Fail, which are explicit policy outcomes, a PermError indicates a fundamental problem with the record itself. Mail servers often treat PermErrors as a hard fail, leading to significant email delivery issues.
Other common issues include broken SPF records due to syntax errors, invalid mechanisms, or even recursive DNS lookups (loops), which can also cause SPF authentication failures. These issues are often difficult to diagnose and fix manually, especially for domains with complex email infrastructures.
The 10-DNS lookup limit explained
SPF records are designed to be concise, but modern email ecosystems often require referencing numerous third-party services. Each include, a, mx, and ptr mechanism in your SPF record triggers a DNS lookup. Once you hit ten of these, any further lookups will result in a PermError.
Understanding universal SPF
Universal SPF isn't a new SPF standard, but rather an ingenious method that leverages existing SPF capabilities to overcome its limitations, particularly the 10-DNS lookup limit. It operates as a service that imports your current SPF policy, flattens it by resolving all include statements and IP addresses into a single, compact record. This SPF flattening process eliminates the need for multiple DNS lookups, thus preventing PermErrors.
The core idea is to replace your complex SPF record with a single, simple include statement that points to the universal SPF service. This service then dynamically serves the correct, flattened SPF policy to inquiring mail servers. It effectively takes a broken SPF policy (one with too many lookups) and makes it functional by serving a compacted version that adheres to the lookup limit.
Think of it as a proxy for your SPF record. Instead of mail servers querying numerous domains to validate your SPF, they query just one: the universal SPF service. This service handles all the complex lookups and dynamically provides a streamlined, valid SPF record. This approach has gained significant traction, being supported by all major providers.
Traditional SPF
Complexity: Requires manual updates for each new sending service. Can become unwieldy with many includes.
DNS lookups: Each include counts towards the 10-lookup limit, leading to PermErrors.
Maintenance: Requires constant monitoring for changes in ESP IPs or policies, risking broken records.
Universal SPF
Simplicity: Replaces multiple includes with a single, streamlined entry. Automatically handles complex DNS resolution.
DNS lookups: Reduces effective DNS lookups to one, bypassing the 10-lookup limit and preventing PermErrors.
Maintenance: Managed externally, reducing the burden on domain administrators to monitor and update SPF records manually.
How universal SPF fixes common policy issues
Universal SPF primarily addresses broken SPF policies by consolidating all your authorized sending sources into a single, compliant record. This is achieved through SPF flattening, where the service dynamically resolves all IP addresses and includes from your original, potentially lengthy SPF record.
When a receiving mail server queries your domain's SPF record, it receives the simplified, flattened version from the universal SPF service. This single record contains all the necessary IP ranges, avoiding the 10-DNS lookup limit entirely. This means that even if your original SPF record would have generated a PermError due to excessive lookups, the universal SPF implementation ensures it passes validation.
Beyond solving the lookup limit, universal SPF services often monitor and update the underlying IP addresses for your included services. This automatic management protects your SPF policy against changes made by your ESPs or other sending services, which could otherwise lead to unforeseen SPF failures. This proactive approach significantly reduces the risk of email delivery disruptions and maintains strong email authentication.
Example of a universal SPF recordDNS
v=spf1 include:_spf.universalspf.org ~all
Implementing universal SPF for your domain
Implementing universal SPF is straightforward. Instead of adding numerous include mechanisms for all your sending services, you replace them with a single include pointing to the universal SPF service. The exact domain to include will be provided by the universal SPF provider. For example, it might look like include:_spf.universalspf.org.
After setting up the universal SPF record, it's crucial to validate your SPF record and monitor your DMARC reports. DMARC reports provide invaluable insights into SPF authentication results, including any PermErrors or other SPF failures. By observing your DMARC data, you can confirm that universal SPF is correctly resolving your policy and improving your deliverability.
Simplifying SPF for robust email delivery
With a properly configured universal SPF setup, your domain's SPF validation should significantly improve, reducing bounces and improving inbox placement. It simplifies a historically complex aspect of email authentication, allowing you to focus on your email campaigns rather than technical DNS management. It works by inactivating SPF terms that cause errors, then serving a cleaned-up and compressed policy on the fly, as confirmed by millions of DMARC data points.
This innovative solution ensures that your email authentication remains robust and compliant with RFC 7208, even as your sending infrastructure grows. It's a critical tool for modern email senders aiming for maximum deliverability and protection against spoofing.
Views from the trenches
Best practices
Actively use DMARC reports to verify universal SPF's effectiveness and identify any lingering issues.
Implement universal SPF as a proactive measure to prevent future SPF lookup limit issues as your email sending infrastructure evolves.
Review your SPF record for any syntax errors or unnecessary entries before implementing universal SPF.
Maintain awareness of all services that send email on behalf of your domain to ensure they are covered by your SPF policy.
Common pitfalls
Relying solely on universal SPF without monitoring DMARC reports to catch any edge cases or misconfigurations.
Forgetting to update the universal SPF service when adding new legitimate sending sources, causing authentication failures.
Misunderstanding that universal SPF is a complete replacement for email authentication, rather than a solution for SPF complexity.
Not thoroughly testing email deliverability after implementing universal SPF to ensure expected results.
Expert tips
Many domain owners and ESPs prefer a looser interpretation of RFC 7208, making universal SPF a practical way to extend SPF utility.
Universal SPF is a 'layer 2' concept that extends SPF functionality in a backwards-compatible way.
While macros are part of RFC 7208, universal SPF applies them ingeniously to solve real-world lookup limit problems.
This solution helps domain operators signal to receiving servers that broken policies should still return a pass/fail result.
Expert view
Expert from Email Geeks says they built an extension to SPF that protects a domain’s delivery against accidents like exceeding 10 DNS lookups, causing lookup loops, or other failures, which is now supported by all major providers.
2021-02-24 - Email Geeks
Marketer view
Marketer from Email Geeks says that while this solution is genius, it feels like a very overengineered fix for a bug that should have been addressed in new RFC iterations.
