- What is the Mail Header Analyzer?
- It is a free tool that parses the raw headers of an email and lays them out in a readable form, showing the servers that handled the message, the time it spent at each hop, and the SPF, DKIM and DMARC authentication results.
- How do I use this tool?
- Open the original message in your mail client, copy the full header block (in Gmail use Show original, in Outlook use Properties or View source), paste it into the box, and the analysis runs instantly in your browser. Nothing you paste is uploaded or stored.
- Why does the mail header matter?
- Headers are the delivery record of an email, so they reveal the true sending path and whether the sender passed authentication, which helps you spot spoofing, phishing and slow relays that a normal inbox view hides.
- How do I read the delivery hops and timing?
- Each Received line is one hop; read them from the bottom (origin) to the top (your server), and the delay shown between hops tells you where a message was held up. Large gaps usually point to the queue or greylisting that caused a delay.
- What does it mean if SPF, DKIM or DMARC shows fail?
- A fail means the message did not authenticate for that check, which can indicate spoofing or a misconfigured sender, though forwarding and mailing lists can legitimately break SPF and DKIM. The tool only reports the results already recorded in the headers; it does not perform live DNS lookups.