SPF Permerror: How to Fix Too Many DNS Lookups

Sender Policy Framework (SPF) is an email authentication method that lets domain owners define which mail servers are permitted to send messages using their domain name. When a message arrives, receiving mail servers check SPF to see whether it came from one of those approved sources before deciding how to treat it.

During SPF validation, a PermError points to a permanent problem in the SPF record that stops it from being evaluated properly. This usually happens when the record goes over the DNS lookup limit or includes structural issues that break how SPF is processed. Instead of failing occasionally, authentication fails every time.

When that happens, even legitimate emails can start looking suspicious to receiving servers. Messages may be rejected, routed to spam, or trigger DMARC failures as well – all because the SPF record itself can’t be reliably evaluated.

If you’re looking to fix SPF PermError, understanding what triggers it is the first step. In this article, we break down the common causes of SPF PermError and explain practical ways to resolve them so your emails authenticate correctly and reach their intended inboxes.

What is SPF Permerror?

An SPF Permerror is a permanent error in your SPF record, meaning there’s something wrong with it that stops it from working.

A Permerror result is returned by receiving mail servers when your SPF record has a critical issue that makes it impossible to evaluate, such as incorrect syntax, too many DNS lookups (over the 10-limit), or invalid mechanisms. Unlike a regular SPF “fail” (which means an email didn’t pass authentication), a Permerror indicates that the SPF record itself is broken or misconfigured. This not only affects deliverability but can also weaken your DMARC protection if SPF is the only mechanism you’re using to align your email.

Why Does SPF Have a 10 DNS Lookup Limit?

You might think the 10 DNS lookup limit in SPF is restrictive, but it’s there for a very good reason.

According to RFC 7208, this limit exists primarily for security and performance purposes. Specifically, it helps protect receiving mail servers from Denial-of-Service (DoS) attacks caused by excessive DNS queries.

Here’s how it could be abused:

A threat actor might create a malicious SPF record that triggers hundreds of DNS lookups by referencing multiple domains or includes. This could be tied to a spoofed domain pretending to be a trusted company. Every time a receiving server tries to validate such an email, it would be forced to resolve all those lookups, slowing down the server or even crashing it.

By capping DNS lookups at 10, SPF helps:

• Maintain email processing performance
• Protect against resource exhaustion attacks
• Improve anti-spoofing reliability by encouraging better SPF record design

What Causes SPF Permerror?

An SPF Permerror can be triggered by several issues, including excessive DNS lookups, syntax errors, misconfigured records, or even overly large SPF entries. Let’s break down the most common causes:

1. SPF syntax errors

Incorrect formatting or invalid syntax in the SPF record can lead to a Permerror, preventing proper evaluation.

Common causes:

• Missing or misplaced characters (e.g., quotes ” or colons 🙂
• Invalid or malformed mechanisms or qualifiers (e.g., using include_spf.example.com instead of include:spf.example.com)
• Incorrect macro definitions or unsupported macros
  

Examples:

❌ v=spf1 include_spf.example.com -all → missing colon in include

❌ v=spf1 +mx a:mail.example.com -all → + qualifier is unnecessary and often misused

2. DNS configuration issues

These involve problems with the DNS setup related to your SPF record.

Common issues:

• SPF record pointing to non-existent or misconfigured domains
• Missing SPF records on referenced domains
• Invalid or deprecated DNS record types (e.g., using SPF-type records instead of TXT)
  

Example:

Your domain references include:spf.partner.com, but spf.partner.com doesn’t exist or lacks a TXT record, leading to SPF evaluation failure.

3. Too many DNS lookups

SPF allows only 10 DNS lookups during record evaluation, as defined in RFC 7208, Section 4.6.4. This is a security measure to prevent abuse (e.g., Denial-of-Service attacks) and keep evaluations lightweight.

What counts as a lookup:

• include
• a, mx, ptr
• exists, redirect
  

Void lookups (queries that return no DNS data) are also limited to 2.

Common cause:

An SPF record with many include: mechanisms or nested includes that collectively exceed the 10-lookup limit.

4. Circular includes

Circular includes occur when SPF records refer back to each other in a loop, creating infinite resolution cycles.

Example:

• Domain A: v=spf1 include:domainB.com -all
• Domain B: v=spf1 include:domainA.com -all

This circular reference causes SPF evaluation to fail, often resulting in a Permerror.

5. Invalid mechanisms or qualifiers

Using unrecognized or deprecated mechanisms in your SPF record can result in a Permerror.

Common mistakes:

• Typos like ip6v instead of ip6
• Unsupported mechanisms such as all:, ptr: used incorrectly
• Using + or ? qualifiers unnecessarily or incorrectly
  

Example:

❌ v=spf1 ptr:mail.example.com -all → discouraged mechanism
❌ v=spf1 ip4v:192.0.2.0/24 -all → invalid mechanism (ip4v should be ip4)

6. Oversized SPF records

SPF records must adhere to size limitations:

• Each string in a TXT record must be ≤ 255 characters
• Total TXT record length should not exceed 512 bytes
  

Causes of oversized records:

• Too many IPs, includes, or mechanisms
• Duplicated or unnecessary entries

Example:

A record like v=spf1 ip4:192.0.2.0/24 ip4:198.51.100.0/24 include:spf1.example.com include:spf2.example.com include:spf3.example.com include:spf4.example.com -all may exceed DNS limits or size constraints.

How Too Many DNS Lookups Break Your Emails

When your SPF record triggers more than 10 DNS lookups, it can seriously disrupt your email delivery. Here’s what can happen:

• Delivery delays: Email servers may slow down processing while trying to evaluate your SPF record, causing delivery delays. 
• Timeout errors: Too many lookups can lead to timeouts during SPF evaluation, causing messages to fail silently or get dropped.
• Rejected emails: Some receiving servers may outright reject or flag emails with SPF Permerror to protect their infrastructure.
• DMARC fails: If your DMARC policy relies on SPF alignment, a failed SPF check can break DMARC and reduce your domain’s trustworthiness.

How to Fix SPF Permerror (Step-by-Step)

Manual Fixes

• Remove unused include mechanisms

Go through each include: in your SPF record and check if it’s still necessary. If it’s linked to a service you no longer use, remove it.

• Replace include with IP addresses (if static)

If an include: just points to a static IP or small IP range, replace it directly with an ip4: or ip6: mechanism to avoid a DNS lookup.

• Eliminate PTR mechanisms

PTR is discouraged by RFC 7208 due to performance and reliability concerns. Remove it entirely to reduce lookups and avoid errors.

• Consolidate include domains

Some services (e.g., email platforms or providers) offer multiple SPF entries. Check their documentation, as often they provide a single consolidated include you can use instead of multiple ones.

• Use ip4 / ip6 where possible

If you know the IPs of your sending servers, add them directly using ip4: or ip6: instead of relying on mechanisms like MX or A that consume lookups.

Best practice: Use an automatic SPF flattening tool

Automatic SPF flattening is the process of dynamically converting multiple “include” statements and other DNS-based lookups into a simplified list of IP addresses. This approach reduces the number of DNS lookups during SPF checks.

Manual SPF flattening may seem like a quick fix, but it comes with serious risks. If your email service provider changes their sending IPs, your SPF record won’t reflect the change unless you update it manually. Hence it requires constant monitoring and manual edits to stay compliant. An outdated IP in your flattened record can cause SPF to fail, affecting email deliverability and DMARC alignment.

PowerSPF is our hosted SPF flattening and optimization tool that automates the entire process, so you never have to worry about lookup limits or IP changes again.

• Auto-updates when vendors change IPs: We keep your SPF record updated in real time.
• One-time setup: Set it once and forget it. No ongoing maintenance.
• Lookup count stays low: Your SPF record stays lean and compliant with RFC guidelines and restrictions.

Key Differences Between SPF Fail And SPF Permerror

Prevent Too Many DNS Loolups and Other SPF Errors

Preventing SPF errors takes ongoing attention, especially as your email infrastructure changes and new third-party services get added over time. A few consistent practices help keep your SPF records valid and safely within protocol limits (even as your setup continues to evolve).

Keeping email service provider settings up to date ensures that authorized sending sources remain aligned with your SPF record. When providers update their sending infrastructure or recommend changes to include domains, failing to reflect those updates can lead to authentication failures.

Reviewing your SPF configuration whenever vendors are added, removed, or replaced is equally important. Marketing platforms, billing systems, support tools, and automation services often send email on behalf of your domain, and each change should trigger a check to confirm your SPF record still reflects all active senders.

Maintaining a periodic audit schedule helps prevent records from growing too complex. Regular reviews make it easier to remove unused include statements, track DNS lookups, and ensure the record stays within the SPF lookup limit before errors occur.

Documenting all services that send email on behalf of your domain provides a clear reference point for future updates. A simple inventory of approved senders reduces guesswork, speeds up troubleshooting, and helps maintain a clean, reliable SPF configuration over time.

Conclusion

SPF Permerror can impact your deliverability, domain health, and security. Simple efforts like removing redundant mechanisms, replacing mechanisms with IP ranges, and monitoring deliverability can go a long way.

And for organizations who wish to avoid the hassle and save time, there are hosted solutions like PowerSPF. Interested in learning how it works and how it can be transformative for your authentication posture? Schedule a free demo today with one of our in-house experts!

Frequently Asked Questions (FAQs)

Can SPF exceed 10 lookups if needed?

No, SPF is strictly limited to 10 DNS lookups during evaluation, as defined in RFC 7208. Exceeding this limit causes a Permerror, and your emails may be rejected or marked as spam.

Can I have multiple SPF records?

No. You should setup only 1 SPF record per domain that authorizes all your sending sources for that domain. Multiple records can invalidate all of them, causing errors.

What’s the safest way to fix Permerror?

The safest way to fix Permerror is to use a hosted SPF solution like PowerSPF to dynamically optimize SPF, with expert support available 24/7.  

Is flattening safe for dynamic IPs?

If your provider uses dynamic IPs, manual flattening can quickly become outdated, causing SPF failures. For dynamic or frequently changing IPs, the safest option is to use a hosted solution which automatically fetches and updates IPs on your behalf. 

• About
• Latest Posts

Maitham Al Lawati

Cybersecurity Expert, CEO at PowerDMARC

Maitham is a tech entrepreneur, cybersecurity expert, CEO and Founder of PowerDMARC with 15+ years of industry experience. Maitham holds a Global MBA from the University of Manchester and various professional certifications including CISSP, CISM, CRISC, and ISC2 CCSP.

Latest posts by Maitham Al Lawati (see all)

• Email Phishing and DMARC Statistics: 2026 Email Security Trends - January 6, 2026
• How to Fix “No SPF record found” in 2026 - January 3, 2026
• SPF Permerror: How to Fix Too Many DNS Lookups - December 24, 2025