SPF Too Many Lookups
The SPF specification (RFC 7208) limits DNS lookups during SPF evaluation to 10. Each include, a, mx, redirect, and exists mechanism counts as one lookup. When organizations use multiple email services (Google Workspace, Microsoft 365, Mailchimp, Salesforce, etc.), each adds include mechanisms that quickly exceed the limit. Exceeding 10 lookups causes an SPF PermError.
Symptoms
- SPF check returns PermError due to lookup count
- Adding a new email service include breaks existing SPF
- Email deliverability degrades after adding new sending services
- SPF validation tools showing 11+ DNS lookups
Common Causes
- Each SaaS email service adding include mechanisms
- Nested includes expanding to multiple levels of lookups
- Using "a" and "mx" mechanisms that each consume a lookup
- Redundant or unnecessary include mechanisms from decommissioned services
Step-by-Step Troubleshooting
- 1
Check current lookup count
Validate your SPF record and count the total DNS lookups including nested includes.
Use SPF Checker → - 2
Flatten SPF record
Replace include mechanisms with their resolved IP ranges to eliminate lookups.
Use SPF Flattener → - 3
Remove unused services
Audit include mechanisms and remove any for services you no longer use.
- 4
Generate optimized SPF
Create a new record with minimal lookups while covering all sending services.
Use SPF Generator → - 5
Verify deliverability
After updating, verify SPF passes for all your sending services.
Use SPF Checker →
Recommended Diagnostic Tools
Monitor SPF Lookup Count
Get alerts when SPF lookup count approaches or exceeds the limit.