SPF DNS Lookup Limit Optimization

Exceeding 10 lookups causes tempfail. Flatten or restructure records to stay under limits.

Steps

1. Inventory include domains
2. Flatten or use subdomain delegation
3. Validate with SPF Checker

FAQ

What counts as a lookup?

include, a, mx, ptr, exists, redirect, exp can introduce lookups and chains.

Validation & Screenshots

SPF Record Validation

1. Run SPF Checker and ensure 10 DNS lookups
2. Resolve nested includes and re-test
3. Send a test email and confirm SPF: PASS in Gmail Show original

Screenshot placeholder (optional): /assets/guides/common/gmail-show-original.png

Outlook Headers (optional)

1. Open View message details in Outlook on the web
2. Confirm SPF verdict in Authentication-Results

Screenshot placeholder (optional): /assets/guides/common/outlook-header-details.png

Platform Validators

• TXT Lookup
• SPF Checker
• Email Health Checker