Fixing SPF PermError and DNS Lookup Limits

SPF PermError (Permanent Error) occurs when your domain's SPF record is misconfigured or exceeds the SPF 10 DNS lookup limit. This is a critical problem that can cause DMARC failures, reduced email deliverability, and emails being rejected or marked as spam by providers like Gmail, Microsoft 365, and Yahoo.

Why SPF PermError Happens

The SPF specification enforces a strict limit of 10 DNS lookups to prevent abuse and reduce server load. Each include:, a, mx, or similar mechanism counts towards this limit. If the total number of lookups exceeds 10, mail servers return a PermError, causing messages to fail authentication.

Common Causes

• Too many third-party services added to SPF via include: statements.
• Redundant or outdated SPF entries that were never cleaned up.
• Misconfigured domains that reference DNS records which no longer exist.
• Multiple marketing, CRM, and ticketing systems all competing for SPF space.

Example of a problematic SPF record:

v=spf1 include:spf.marketing.com include:_spf.crm.com include:mail.security.com 
include:_spf.support.com include:email.gateway.com -all
    

This record may already exceed the 10-lookup limit when each include expands, resulting in a PermError.

The SPF Guru Solution – Unlimited Lookups, No PermError

SPF Guru provides a free, community-supported solution to completely bypass the SPF lookup limit. By adding just two DNS records to your domain, you can safely exceed the 10-lookup threshold without breaking SPF validation or triggering a PermError.

How It Works

SPF Guru uses a unique macro-based DNS response system. Instead of directly publishing all your include: statements, you point your domain to SPF Guru, which dynamically resolves and flattens everything for you.

Add the following two lines to your SPF record directly after "v=spf1 ":

include:i.%{ir}._d.%{d}.my.spf.guru
~include:z.%{ir}._d.%{d}.my.spf.guru
    

• The first include: is the primary mechanism used by receiving mail servers.
• The second ~include: acts as a soft fallback, ensuring stability and unlimited scalability.

This setup allows unlimited SPF lookups to be performed dynamically without violating the SPF specification.

Benefits of Using SPF Guru

• ✅ Fixes SPF PermError caused by too many DNS lookups.
• ✅ Works with unlimited third-party services, no matter how complex your email infrastructure is.
• ✅ Free, community-supported solution — no licensing fees.
• ✅ Simplifies SPF management and reduces maintenance overhead.
• ✅ Helps achieve DMARC compliance and improves email deliverability.

SPF Guru is ideal for mail administrators and IT professionals looking to quickly resolve SPF lookup issues without expensive commercial tools.

Why You Should Fix SPF PermError Now

Leaving SPF PermError unresolved can have serious consequences:

• Legitimate emails being rejected or quarantined.
• DMARC reports filled with authentication failures.
• Damage to your domain’s sending reputation and trust.
• Increased likelihood of blacklisting by major email providers.

Fixing the issue with SPF Guru takes minutes and can save hours of troubleshooting.

Disclaimer

The SPF Guru service is provided free of charge and is community-supported. While every effort is made to maintain reliable uptime and accuracy, SPF Guru is offered on a best-effort basis without guarantees of availability or performance.

Always validate changes in a safe test environment before deploying to production systems. SPF Guru is not intended to be the sole method of ensuring DMARC compliance. For the best protection, we strongly recommend using DKIM alongside SPF.

Get Support

If you need help or have questions, you can:

• Report an issue via GitHub: github.com/smck83/spf.guru/issues
• Email us directly: [email protected]

Support is provided on a volunteer, best-effort basis.

By using SPF Guru, you accept the terms outlined in this disclaimers.