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SPF Flattening Documentation & FAQ

Everything you need to know about SPF flattening, email deliverability, and managing your DNS records for optimal email authentication. Learn how to prevent email delivery failures and improve your sender reputation.

Getting Started

Why should I use SPF flattening?

SPF (Sender Policy Framework) records have a DNS lookup limit of 10. If you use many email services or have complex includes, you can easily exceed this limit, causing email delivery failures. SPF flattening combines all includes and mechanisms into a single, flat record, ensuring you stay within the limit and your emails are delivered reliably. With spFlat! you get a modern UI to manage your domains, see color-coded SPF terms, and get instant feedback on DNS lookups and record health. This prevents common email authentication issues that can lead to messages being marked as spam or rejected entirely.

Technical Details

How does SPF flattening work?

SPF flattening recursively resolves all 'include', 'a', 'mx', and other mechanisms in your SPF record, collects all the resulting IP addresses, and generates a new SPF record with only IP addresses and minimal mechanisms. This reduces DNS lookups and avoids the 10-lookup limit. Our advanced algorithm works as follows: 1. Parses your existing SPF record 2. Resolves all DNS lookups for includes and mechanisms 3. Collects all authorized IP addresses 4. Generates a flattened record with direct IP addresses 5. Validates the final record for compliance Our UI shows both the original and flattened SPF, with a DNS lookup count and color-coded warnings if you exceed the safe limit.

Does SPF flattening affect DMARC or DKIM?

No, SPF flattening only affects the SPF record itself. DMARC and DKIM are separate mechanisms for email authentication: • DMARC (Domain-based Message Authentication, Reporting & Conformance) uses SPF and DKIM results to make policy decisions • DKIM (DomainKeys Identified Mail) uses cryptographic signatures attached to emails • SPF (Sender Policy Framework) authorizes which IP addresses can send email for your domain SPF flattening actually improves DMARC compliance by ensuring SPF checks pass consistently, leading to better DMARC alignment and overall email security.

What is the SPF lookup limit and why does it matter?

The SPF lookup limit is a hard limit of 10 DNS lookups that can be performed when evaluating an SPF record. This limit exists to prevent infinite loops and reduce DNS query load. Common causes of exceeding the limit: • Multiple email service providers (Google, Microsoft, Mailgun, etc.) • Complex include chains • Nested SPF records • Using 'a' and 'mx' mechanisms excessively When the limit is exceeded, the SPF check fails with a "permerror" result, causing emails to be rejected or marked as spam. spFlat! solves this by converting all includes to direct IP addresses, typically reducing your lookup count to 1-2.

Troubleshooting

What are the risks of not flattening my SPF record?

If your SPF record exceeds the DNS lookup limit, recipient mail servers may reject or mark your emails as spam. Common consequences include: • Email delivery failures to major providers (Gmail, Outlook, etc.) • Reduced sender reputation over time • Increased spam folder placement • Failed email authentication checks • Potential blacklisting of your domain Our tool highlights when you exceed the limit with a red warning, so you can take action before problems occur. Regular monitoring and flattening ensure consistent email deliverability.

Best Practices

How often should I flatten my SPF record?

You should flatten your SPF record whenever you: • Add or change email providers • Notice delivery issues • Receive SPF-related bounce messages • Add new services that send email on your behalf Some providers change their sending IPs frequently, especially cloud-based services. Our tool makes it easy to update and review your SPF records at any time, with automated monitoring to alert you when changes are needed. We recommend checking your SPF records monthly and after any email infrastructure changes.

How does SPF flattening improve email deliverability?

SPF flattening significantly improves email deliverability by: • Preventing SPF lookup failures that cause email rejection • Reducing DNS query time and potential timeouts • Ensuring consistent SPF evaluation across all email providers • Improving sender reputation through reliable authentication • Reducing the risk of being flagged as spam Studies show that properly configured SPF records can improve inbox placement by up to 10-15%. With spFlat!'s automated management, you maintain optimal SPF configuration without manual intervention, ensuring consistent delivery performance.

Automation

Can I automate SPF flattening?

Absolutely! spFlat! is designed to fully automate SPF flattening for you. Our comprehensive automation features include: • Continuous monitoring of your domains and SPF records • Automatic detection of provider IP changes • Real-time flattening and updates • Color-coded dashboard showing record health • Instant alerts for DNS lookup limit violations • One-click DNS updates with copy-to-clipboard functionality With organization-aware domain management, intuitive modals for adding/editing/deleting records, and a focus on accessibility and modern UX, spFlat! is the easiest and most reliable way to keep your SPF records healthy and your email deliverability high. Our automation saves you hours of manual work while ensuring your email infrastructure remains secure and compliant.

Organisation

What are the organisation member roles and permissions?

Admin

Full control: manage domains, billing, members and view audit logs.

Billing

Can view invoices and manage subscription, but not edit domains or members.

Default

Read-only access to domains and SPF previews; no billing or member management.

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