How to resolve SPF SOFTFAIL errors when moving to a dedicated IP address?

Key findings

• Multiple SPF records: Having more than one SPF TXT record for a single domain is invalid and will cause SPF authentication to fail, often resulting in a SOFTFAIL.
• Consolidation is key: All authorized sending mechanisms (IPs, includes, a records, mx records) for a domain must be listed within a single SPF record. If you have multiple services sending email, their SPF mechanisms need to be combined into one record.
• New IP authorization: When moving to a dedicated IP, ensure this new IP address (or the corresponding 'include' mechanism from your ESP) is explicitly added to your consolidated SPF record.
• DNS propagation: After any DNS changes, allow sufficient time for records to propagate across the internet, typically up to 24 hours, depending on your DNS TTL (time to live) settings.
• SPF alignment: For DMARC to pass, either SPF or DKIM must align with the 'From' domain. If your ESP handles the return-path domain, SPF alignment for your primary domain might not be strictly necessary, provided DKIM alignment is in place.

Key considerations

• Validation tools: Utilize online SPF validation tools to verify your consolidated SPF record is correctly configured and that your new IP is authorized. This helps in troubleshooting SPF failures.
• DNS TTL settings: Be mindful of your DNS record's TTL. A lower TTL can speed up propagation for changes, but setting it too low can increase DNS query load.
• Gradual IP warmup: Even with correct SPF, a new dedicated IP needs proper IP warmup to build sender reputation.
• External SPF management: If using a third-party service for DMARC or SPF management (e.g., OnDMARC, AutoSPF), confirm their instructions for adding new IPs. They might manage the SPF record on their end, requiring you only to include their specific mechanism.

Key opinions

• Immediate checks: The first step for marketers is to confirm if the new IP address has been correctly added to the subdomain's SPF record and is resolving in DNS.
• Root cause of SOFTFAIL: A SOFTFAIL for SPF almost always points to an issue with the SPF record itself, particularly when moving to new IPs.
• DNS propagation time: Marketers frequently forget or underestimate the time needed for DNS changes to settle, which is typically around 24 hours.
• Multiple SPF records: Many marketers identify that having multiple SPF TXT records is a common, invalid configuration that must be corrected by combining them into one.

Key considerations

• Impact on warmup: An SPF SOFTFAIL prevents proper IP warmup, hindering deliverability and potentially causing emails to land in spam. This is critical for new IP and subdomain warmup.
• Troubleshooting process: Marketers should systematically check for common DNS errors before escalating to their ESP, as simple fixes often resolve these issues.
• DMARC alignment: Understanding that DMARC only requires either SPF or DKIM alignment, but not both, helps in diagnosing issues where one passes and the other fails.
• ESP role: Relying on ESPs to resolve such issues can be slow, making it beneficial for marketers to understand basic DNS configurations themselves to resolve email deliverability issues.
• Return-path domain impact: SPF records are only needed for the domain specified in the email's return-path. If an ESP uses its own return-path domain, your subdomain might not need an SPF record for alignment, as highlighted in community discussions.

Key opinions

• Consolidate SPF records: Experts stress that there should only be one SPF TXT record per domain. Multiple SPF records for the same domain are invalid and cause issues.
• SPF and DMARC alignment: For DMARC to pass, only one of SPF or DKIM needs to align with the 'From' domain. This means that if DKIM is properly configured, SPF SOFTFAIL might not necessarily lead to DMARC failure.
• Return-path domain importance: The SPF record is only relevant for the domain specified in the mail's return-path. If an ESP uses its own return-path domain, then SPF for your primary domain might not be necessary for DMARC alignment.
• Beware of bad guidance: Historical advice sometimes led to creating unnecessary SPF records for subdomains not involved in the return-path, contributing to configuration bloat.
• Specialized SPF services: If using a DMARC or SPF management service, confirm their specific instructions as they might handle the SPF record internally via their dashboard, requiring only their include mechanism in your DNS.

Key considerations

• DNS syntax: Verify the exact syntax when combining SPF records to avoid typos or incorrect formatting that could invalidate the record. This is crucial for proper email authentication.
• Testing tools: Rely on reputable SPF validation tools to confirm your record's validity after changes. A tool like Kitterman's SPF validator can provide real-time feedback.
• IP warm-up continuity: Fixing SPF issues promptly ensures that your dedicated IP warm-up proceeds without interruption.
• Monitoring and re-checking: After implementing fixes, continuously monitor deliverability and re-check SPF status to ensure the problem is fully resolved and doesn't reappear, as suggested by industry experts.

Key findings

• Single SPF record rule: RFC 7208 mandates that a domain or subdomain must have only one SPF TXT record. Multiple records are considered invalid.
• Include mechanisms: The SPF record uses 'include' mechanisms to refer to SPF records of third-party senders (like ESPs) rather than listing their IPs directly, helping manage record length and complexity.
• IP address inclusion: For dedicated IPs, the 'ip4' or 'ip6' mechanism must be used within the SPF record to explicitly authorize the new IP address.
• Qualifier importance: The SPF record must end with a qualifier, typically '~all' (SOFTFAIL) or '-all' (HARDFAIL), to define the policy for unauthorized senders.

Key considerations

• DNS lookup limits: SPF records have a limit of 10 DNS lookups. Exceeding this limit will result in a PermError. Consolidating records helps manage this, as discussed in our guide on SPF DNS timeout issues.
• Syntax and validation: Adhere strictly to the SPF record syntax. Incorrect formatting can render the entire record invalid.
• SPF mechanisms: Understand the different SPF mechanisms (e.g., 'a', 'mx', 'ptr', 'ip4', 'ip6', 'include', 'exists', 'redirect', 'exp') and their impact on authentication. Knowing what SPF stands for is the first step.
• DMARC policy interaction: A SOFTFAIL for SPF when DMARC is enforced can still lead to delivery issues unless DKIM passes alignment. This highlights the interdependency of these protocols.