Why SPF Matters
Sender Policy Framework (SPF) is the first line of defense against email spoofing. It lets domain owners specify which mail servers are authorized to send email on their behalf. Without a properly configured SPF record, attackers can forge emails that appear to come from your domain.
Analyzing SPF with DomainDetective
DomainDetective provides comprehensive SPF analysis that goes beyond simple record lookup. It validates the entire SPF chain, checks for common misconfigurations, and provides actionable recommendations.
Using the Online Tools
The fastest way to check an SPF record is our online SPF Lookup tool. Simply enter a domain name and click "Analyze" - all processing happens client-side in your browser via DNS-over-HTTPS.
Using the C# Library
var healthCheck = new DomainHealthCheck();
await healthCheck.VerifySPF("example.com");
var spf = healthCheck.SpfAnalysis;
Console.WriteLine($"Record: {spf.SpfRecord}");
Console.WriteLine($"DNS Lookups: {spf.DnsLookupCount}/10");
Console.WriteLine($"Issues: {spf.Issues.Count}");
Using PowerShell
$results = Test-DomainHealth -DomainName "example.com" -HealthCheckType SPF
$results.SpfAnalysis | Format-List
$results.SpfAnalysis.Issues | Format-Table
Common SPF Issues
DomainDetective checks for over 20 SPF-specific issues including:
- Too many DNS lookups - SPF has a 10-lookup limit
- Missing
-allmechanism - Domains should enforce SPF with-all - Deprecated
ptrmechanism - Should be avoided per RFC 7208 - Include chain loops - Circular references in SPF includes
- Duplicate IP ranges - Redundant entries that waste lookup budget
Next Steps
- Try the SPF Lookup tool online
- Read the C# API documentation for advanced usage
- Check out DMARC analysis for full email authentication coverage