Authentication & Relay Diagnostics
Email Header Analyzer
Paste raw email headers to diagnose SPF, DKIM, and DMARC authentication status, trace mail relay delivery hops, and detect email spoofing.
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Understanding Email Authentication Headers
SPF (Sender Policy Framework):
SPF allows domain owners to publish a list of authorized IP addresses that are permitted to send emails on their behalf. A "pass" ensures the sender server is legitimate.
DKIM (DomainKeys Identified Mail):
DKIM attaches a cryptographic digital signature to every outgoing email. The receiving server uses the sender's public DNS key to verify that the message body was not altered in transit.
DMARC (Domain-based Message Authentication):
DMARC ties SPF and DKIM together, instructing receiving servers how to handle messages that fail authentication (e.g. "none", "quarantine", or "reject").