SPF Record
Raw Checker
Analyze SPF record syntax and mechanisms.
Validate SPF without DNS lookup.
Analyze SPF Record
Paste an SPF record to validate syntax and analyze mechanisms
Enter the complete SPF record including v=spf1
Syntax Check
Validate SPF record format
DNS Lookups
Count DNS lookup mechanisms
Best Practices
Get optimization suggestions
Why Analyze SPF Records?
SPF records can fail due to syntax errors, too many DNS lookups, or incorrect mechanisms. This tool helps identify issues before deploying to DNS.
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SPF record analysis guide
Understanding SPF mechanisms, qualifiers, and common optimization techniques for better email authentication.
SPF mechanism types
include: - Reference other SPF records
Authorizes servers from another domain's SPF record. Counts as one DNS lookup.
ip4/ip6 - Direct IP authorization
Directly authorizes specific IPv4 or IPv6 addresses. No DNS lookup required.
a/mx - Use domain records
Authorizes servers listed in A or MX records. Each counts as one DNS lookup.
all - Catch-all policy
Defines what to do with emails from unmatched servers. Usually ~all or -all.
Understanding qualifiers
+ Pass (default) - Authorize the server
If no qualifier is specified, + is assumed. Emails pass SPF authentication.
~ Softfail - Mark as suspicious
Recommended for ~all. Emails are marked but not rejected.
- Fail - Reject the server
Strong policy that rejects emails from unauthorized servers.
The 10 DNS lookup limit
The most common SPF failure is exceeding the 10 DNS lookup limit. Each include, a, mx, ptr, and exists mechanism counts toward this limit. Nested includes also count - a single include statement might trigger multiple lookups.
Large organizations often hit this limit when including multiple third-party services like Google Workspace, Microsoft 365, Mailchimp, and SendGrid. The solution is to use IP addresses directly or consolidate includes through SPF flattening.
Simplify SPF management
InboxKit automatically optimizes SPF records and manages the 10-lookup limit