What are the best tools and practices for consolidating SPF records?
Matthew Whittaker
Co-founder & CTO, Suped
Published 28 Apr 2025
Updated 16 Aug 2025
8 min read
Sender Policy Framework (SPF) records are a cornerstone of email authentication. They specify which mail servers are authorized to send email on behalf of your domain, helping to prevent spoofing and phishing attacks. However, as organizations adopt multiple email sending services (like marketing platforms, CRM systems, and transactional email providers), managing SPF can quickly become complex. Each service often requires its own include mechanism in your SPF record, leading to potential issues.
The primary challenge arises from the SPF 10-DNS lookup limit. If your SPF record requires more than 10 DNS lookups to validate, it will fail, causing legitimate emails to be marked as spam or rejected outright. This is why consolidating SPF records is not just a best practice, but a critical step for maintaining good email deliverability and protecting your domain's reputation. Let's explore the tools and practices that help you navigate this complexity.
The 10-DNS lookup limit is a hard limit imposed by the SPF specification (RFC 7208). Each time your SPF record includes mechanisms like a, mx, ptr, exists, or include, it triggers a DNS lookup. Exceeding this limit causes a PermError, which essentially tells receiving mail servers to treat your email as unauthenticated, leading to delivery failures.
The impact of a PermError is severe. When an SPF record fails due to too many lookups, your email's authentication status is compromised. This directly affects your email deliverability, often resulting in messages landing in recipients' spam folders or being rejected outright. This can also negatively impact your DMARC alignment, as SPF is one of the authentication methods DMARC relies on. Properly consolidating your SPF record is crucial to avoiding these pitfalls and ensuring your emails reach their intended inboxes.
The goal is to have a single, comprehensive SPF TXT record per domain. Multiple SPF TXT records (e.g., v=spf1 include:example.com ~all and v=spf1 include:another.com ~all) for the same domain are not allowed and will also cause authentication failures. Properly consolidating ensures that all legitimate sending sources are authorized without breaching the lookup limit or creating conflicting records.
When creating or modifying your SPF record, it's crucial to understand the different mechanisms and their impact on DNS lookups. Some mechanisms require a DNS lookup, while others do not. Be mindful of how each mechanism contributes to your total lookup count to stay within the 10-lookup limit.
No DNS lookup:ip4, ip6, all, exp. These refer to IP addresses directly or provide explanations without requiring DNS queries.
One DNS lookup:a, mx, include, redirect. Each of these mechanisms triggers a single DNS query to resolve.
Two DNS lookups:ptr. While less common due to performance implications, this mechanism can result in two DNS lookups.
Avoid the plus all qualifier
Using the +all (pass) qualifier at the end of your SPF record is a common pitfall. This tells receiving servers to accept email from *any* source, effectively nullifying the protection SPF provides and making your domain vulnerable to spoofing. Always opt for ~all (softfail) or -all (fail) to properly define your sending policy and enhance your domain reputation.
Manual consolidation techniques
The first step in manual consolidation is to identify every service that sends email on behalf of your domain. This includes your primary email provider, marketing automation platforms, CRM systems, transactional email services, and even internal applications. Gather all their required SPF include mechanisms or IP addresses.
Once you have a list of all necessary include statements and IP addresses, you can combine them into a single SPF record. Remember, an SPF record must start with v=spf1 and end with a qualifier like ~all or -all. Each mechanism is separated by a space. This allows you to merge all your sending sources into one comprehensive record. For detailed instructions on how to format your SPF TXT records, including how to add domain include statements and avoid DNS size issues, you can refer to our guide on formatting SPF TXT records.
When adding mechanisms like a or mx, be aware that they each count as one DNS lookup. Use them only if your mail server IP is directly associated with your domain's A or MX records. Direct ip4 or ip6 mechanisms are preferable when possible, as they do not consume DNS lookups. They directly specify IP addresses or ranges that are authorized to send email. For example, ip4:192.0.2.1 would explicitly authorize that IP address without any additional lookups. This helps in optimizing your SPF record to stay within the lookup limit, especially when managing multiple email sending services.
For organizations with a large number of email sending services, manually consolidating SPF records can be time-consuming and prone to errors. This is where SPF flattening services come into play. These services dynamically resolve all include mechanisms into a single list of IP addresses, presenting them as an ip4 or ip6 mechanism. This helps you stay within the 10-lookup limit without manual intervention each time a provider changes its IP ranges.
Automated SPF flattening services offer significant benefits. They continuously monitor your included domains for changes in their SPF records, automatically updating your flattened record. This is crucial because third-party service providers often change their sending IPs without notice, which can break your SPF if not managed properly. By automating this, you reduce the risk of SPF authentication issues and maintain consistent email deliverability.
When evaluating an SPF flattening service, consider its reliability, update frequency, and whether it integrates with other email security protocols. Some tools offer features like SPF compression, which can reduce the DNS footprint. You can learn more about how these services work in our guide on SPF flattening and management. Additionally, services that provide DMARC reporting integration can help identify legitimate senders you might have missed in your SPF record.
Manual consolidation
Process: Requires identifying all sending sources, merging include statements, and manually adding IP addresses into a single SPF TXT record.
Maintenance: High. Requires continuous manual monitoring for changes in third-party SPF records and updating your domain's SPF record accordingly.
Lookup limit: Challenging to stay within the 10-DNS lookup limit, especially with many email services. Manual calculations are prone to error.
Automated SPF flattening
Process: Set up a single include or redirect to the flattening service, which dynamically resolves all IPs. For example, include:spf.autospf.com.
Maintenance: Low. The service automatically monitors and updates the resolved IP list, reducing manual effort.
Lookup limit: Effortlessly stays within the 10-DNS lookup limit by presenting all authorized IPs directly.
Best practices for ongoing SPF management
Consolidating your SPF record is an ongoing process, not a one-time setup. Regularly monitor your SPF record and its DNS lookups to ensure it remains valid and within the allowed limits. Tools that provide blacklist monitoring can also indicate underlying SPF issues if your emails start to land on blocklists (or blacklists). Many MXToolbox-like tools allow you to check your current SPF record for compliance.
As your organization evolves, so do your email sending practices. Periodically review your list of authorized sending services. If you stop using a particular service, promptly remove its include statement or IP range from your SPF record. This reduces complexity and helps ensure that only necessary entries consume your DNS lookups. Pay close attention to the MAIL FROM (or return-path) address used by your providers. Often, third-party senders use their own subdomains for MAIL FROM, meaning their SPF record is checked, not yours. In such cases, including them in your domain's SPF record may be unnecessary.
SPF is just one piece of the email authentication puzzle. For robust email security and optimal deliverability, you should also implement DKIM (DomainKeys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting, and Conformance). DKIM provides a digital signature for your emails, while DMARC instructs receiving servers on how to handle emails that fail SPF or DKIM authentication. Together, these protocols create a powerful defense against email fraud and significantly boost your inbox placement rates. You can find more information on the best practices for setting up SPF, DKIM, and DMARC in our comprehensive guide.
Using the appropriate SPF qualifier
Always use ~all (softfail) or -all (fail) at the end of your SPF record. +all will cause all emails to pass SPF, regardless of the source, opening your domain to abuse and drastically hurting your deliverability.
Views from the trenches
Best practices
Always maintain a single SPF record per domain to prevent validation issues and ensure consistent policy enforcement.
Regularly audit your SPF record for accuracy, especially after adding or removing email sending services.
Prioritize using IP addresses directly (ip4, ip6) in your SPF record when possible to avoid DNS lookups.
Implement SPF alongside DKIM and DMARC for a robust email authentication strategy and improved deliverability.
Common pitfalls
Exceeding the 10-DNS lookup limit in your SPF record, leading to authentication failures and emails going to spam.
Having multiple SPF TXT records for the same domain, which violates RFC standards and causes SPF validation errors.
Using the '+all' (pass) qualifier, which authorizes all senders and makes your domain vulnerable to spoofing.
Forgetting to remove outdated 'include' statements for services no longer used, contributing to lookup bloat.
Expert tips
Consider SPF flattening services for complex environments with many third-party email providers.
Analyze DMARC reports to identify legitimate sending sources that might be missing from your SPF record, improving coverage.
Distinguish between the visible 'From' address and the 'MAIL FROM' (return-path) address when configuring SPF; only the 'MAIL FROM' domain is checked for SPF.
Regularly test your SPF record with an SPF checker tool after any changes to ensure it's correctly configured.
Expert view
Expert from Email Geeks says a key factor for consolidating SPF records is to ensure regular checks on your include and DNS lookups because IP blocks are periodically added or removed by providers, which can lead to failures if not monitored.
2022-08-12 - Email Geeks
Marketer view
Marketer from Email Geeks says they have used Auto SPF for SPF consolidation and found it to work effectively, helping them manage their SPF records without issues.
2022-08-12 - Email Geeks
Optimising your SPF records for better deliverability
Consolidating your SPF records is an indispensable practice for any organization aiming for reliable email deliverability and strong domain security. Adhering to the SPF 10-DNS lookup limit is paramount, as exceeding it can severely impact your emails' ability to reach the inbox. Whether you opt for manual merging or leverage automated SPF flattening tools, the goal remains the same: a single, optimized SPF TXT record that accurately reflects all your legitimate sending sources.
Remember to continuously monitor your SPF record, promptly remove outdated entries, and avoid the dangerous +all qualifier. By combining these best practices with robust DKIM and DMARC implementations, you build a comprehensive email authentication framework that protects your domain from malicious actors and ensures your important communications consistently reach their audience.
MXToolbox-like tools allow you to check your current SPF record for compliance.
