Email Domain Security Analyzer
Evaluates domain email spoofability and SPF supply-chain risks strictly using passive DNS record analysis.
The Email Domain Security skill transforms Claude into an expert email authentication auditor capable of delivering rigorous, defensible email-spoofability verdicts solely from published DNS TXT records. Grounded in RFC 7208 and RFC 7489 standards, it clarifies the critical distinction between envelope MAIL FROM and visible header From addresses, explaining why SPF -all fails to prevent spoofing without DMARC enforcement. It systematically identifies SPF PermError conditions (including the 10-lookup and 2-void-lookup limits), DMARC subdomain policy inheritance pitfalls, duplicate records, and high-risk SPF-include takeovers with strict transient-versus-NXDOMAIN discipline, providing client-ready security findings without sending a single probe or email.