Summary
Dealing with overstuffed SPF records exceeding the 10 DNS lookup limit requires a multi-faceted approach. Documentation highlights the importance of the limit and potential deliverability issues. Experts and marketers suggest options such as simplifying SPF records by removing unnecessary includes, relying on DKIM (and DMARC) as alternative authentication methods, employing SPF flattening (with careful maintenance), utilizing subdomains or dedicated sending domains, and regularly auditing/optimizing SPF records. Hosted SPF services and external authentication services can also resolve the lookup limit. The key is to ensure that the chosen methods are implemented correctly and maintained to achieve optimal email deliverability and authentication.
Key findings
- 10 Lookup Limit: SPF records are limited to 10 DNS lookups.
- DKIM/DMARC Reliance: DKIM and DMARC provide alternative authentication and should be used alongside SPF.
- SPF Flattening: SPF flattening reduces lookups but requires continuous IP monitoring.
- Sub/Dedicated Domains: Using subdomains or dedicated sending domains simplifies SPF management.
- Regular Audits: Regularly auditing and removing obsolete entries keeps SPF records lean.
- Hosted SPF: Hosted SPF services bypass the lookup limit.
- Record Optimization: Regular review and optimization of SPF records are crucial.
- Tools and Checkups: Tools exist to identify includes that contribute to the DNS lookup limit.
Key considerations
- Maintenance: SPF flattening requires ongoing maintenance to update IP addresses.
- ISP Forgiveness: Relying on ISP leniency is not a reliable long-term solution.
- Correct Setup: Ensure correct SPF, DKIM, and DMARC setup for optimal email deliverability.
- Potential Bad Guidance: Be cautious of potentially poor advice from ESPs regarding SPF configuration.
- Ongoing Effort: Managing SPF records requires continuous monitoring and optimization.
- External Cost: Implementing and maintaining external services requires money.
What email marketers say
13 marketer opinions
When SPF records exceed the 10 DNS lookup limit, several options exist. These include relying solely on DKIM, employing SPF flattening (though this requires ongoing maintenance), using subdomains for different email streams, migrating to dedicated sending domains, regularly auditing and removing obsolete entries, and using external services to manage SPF and DKIM. Hosted SPF services, like those offered by Proofpoint, can also resolve lookup limits. It's generally advised to use SPF in conjunction with DKIM and DMARC for robust email authentication.
Key opinions
- DKIM Reliance: DKIM can serve as a robust alternative to SPF when SPF records are too complex.
- SPF Flattening: SPF flattening reduces lookups but requires constant IP address monitoring.
- Subdomain Usage: Using subdomains for different email types simplifies SPF records.
- Dedicated Domains: A dedicated sending domain allows for a more streamlined SPF record.
- Record Auditing: Regularly auditing and removing old entries keeps SPF records lean.
- Hosted SPF: Hosted SPF services bypass the lookup limit.
- External Services: External services can manage SPF and DKIM complexities.
- Importance of Checkup Tools: By checking the SPF record, you can identify which includes are causing additional lookups, and see if any can be removed or consolidated.
Key considerations
- Maintenance: SPF flattening requires ongoing monitoring and updates.
- Complexity: Consider the complexity of implementing and managing different solutions.
- Authentication Standards: Ensure proper SPF, DKIM, and DMARC implementation for best results.
- Service Costs: External services may incur additional costs.
- Business Migration: The business may need to think about a full domain migration
Marketer view
Email marketer from StackOverflow mentions using a dedicated sending domain or subdomain for email marketing. This allows for a simpler SPF record that only includes the necessary services for that specific sending domain, reducing the risk of exceeding the lookup limit.
25 Jul 2021 - StackOverflow
Marketer view
Email marketer from Reddit suggests migrating entirely to DKIM. If SPF is too difficult to manage, DKIM offers a robust alternative for authentication without the DNS lookup limitations of SPF. It involves digitally signing emails, which is verified by the receiving server.
18 Jul 2022 - Reddit
What the experts say
4 expert opinions
Experts suggest several approaches to handling overstuffed SPF records exceeding DNS lookup limits. These include reviewing and optimizing existing records by removing obsolete entries and consolidating includes, using dedicated domains for the 5321.from, and taking the opportunity to create a streamlined SPF record when migrating to a new ESP. Ignoring the issue, though some ISPs are forgiving, is not recommended.
Key opinions
- Record Optimization: Regular review and optimization of SPF records are crucial.
- Dedicated Domains: Using dedicated domains for sending can simplify SPF records.
- ESP Migration: Migrating to a new ESP provides an opportunity to create a lean SPF record.
- Prioritization: Prioritize essential sending sources within the SPF record's lookup limit.
Key considerations
- ISP Forgiveness: Relying on ISP leniency is not a sustainable solution.
- Bad Guidance: Be cautious of bad guidance from ESPs regarding SPF setup.
- Ongoing Review: SPF record management requires continuous effort.
Expert view
Expert from Word to the Wise talks about migrating to a new ESP, that is a good opportunity to address the SPF record. Work with the new ESP to create a lean and optimized SPF record that only includes the necessary sending sources.
30 Dec 2024 - Word to the Wise
Expert view
Expert from Email Geeks explains that a significant problem is people publishing SPF for the wrong domain and ESPs providing bad guidance, recommending dedicated domains for the 5321.from.
18 Oct 2024 - Email Geeks
What the documentation says
4 technical articles
Documentation emphasizes the 10 DNS lookup limit in SPF records, highlighting potential deliverability issues if exceeded. Suggested solutions include simplifying SPF records by removing unnecessary includes, utilizing alternative authentication methods like DKIM, and ensuring proper SPF, DKIM, and DMARC configuration and alignment. Utilizing DKIM can assist when SPF is problematic.
Key findings
- 10 Lookup Limit: SPF records have a strict limit of 10 DNS lookups.
- Deliverability Impact: Exceeding the lookup limit can negatively impact email deliverability.
- DKIM Alternative: DKIM provides an alternative authentication method when SPF is problematic.
- SPF, DKIM, DMARC: Proper configuration of SPF, DKIM, and DMARC is essential for email authentication.
- DMARC Alignment: Alignment with DMARC ensures proper email deliverability.
Key considerations
- Simplification: Regularly simplify SPF records by removing unnecessary includes.
- Configuration: Ensure correct setup for all sending domains.
- Authentication Combination: Leverage SPF, DKIM, and DMARC together for robust email authentication.
Technical article
Documentation from Microsoft answers that for Microsoft 365, it's essential to configure SPF, DKIM, and DMARC correctly. While SPF has its limits, combining it with DKIM can improve email deliverability and authentication. Ensure SPF is set up for all sending domains.
19 Dec 2021 - Microsoft
Technical article
Documentation from Google Workspace Admin Help explains that SPF records have a limit of 10 DNS lookups. Exceeding this limit can cause SPF checks to fail, impacting email deliverability. They suggest simplifying SPF records by removing unnecessary includes or using alternative authentication methods like DKIM.
12 Jan 2024 - Google Workspace Admin Help
How can I optimize my SPF record to stay within the lookup limit when using multiple email sending services?
How do I properly set up SPF and DKIM records for email marketing, including handling multiple SPF records, IP ranges, bounce capturing, and Google Postmaster Tools verification?
How do I set up an SPF record when using multiple email sending services?
How important is the 10 DNS lookups limit on SPF records?
How should I combine SPF records and what domain should I use with SendinBlue?
Is it bad for email deliverability to send from a non-existent email address?
