How to use the Email Header Analyzer
- 1. Copy the raw headersGmail: ⋮ › Show original. Outlook: File › Properties › Internet headers.
- 2. Paste and analyseDrop the headers into the box and press Analyse.
- 3. Read the verdictCheck authentication, the hop list and the warning signs.
What the analyzer looks at
- SPF checks that the sending server is allowed to send for the Return-Path domain.
- DKIM checks a cryptographic signature added by the sending domain.
- DMARC checks that SPF or DKIM passed for the domain shown in From:, and tells receivers what to do if not.
- Received lines are stamped by each server along the way. The tool lists them from sender to you, with the delay at each hop.
- Address mismatches: a From domain that differs from Return-Path or Reply-To.
Reading the sample
The built-in sample is invented for practice and uses reserved example domains and documentation IP addresses. It travels through 3 hops in 11 seconds. SPF passes, but only for mailer-example.net, the bulk sender in Return-Path. DKIM is missing and DMARC fails for examplebank.com, the brand in From:. Replies would go to a free-mail address, and the subject pushes urgency. Five warning signs together mean: do not click, report it.
Only the Received lines added by your own provider can be trusted; anything below them can be forged by the sender. A pass on every check does not prove an email is safe, because criminals also register look-alike domains with perfect SPF and DKIM, so judge the content and links too. Everything is parsed in your browser. Extract links and IPs from the message body with the IOC extractor, defang them for a report with the URL defang tool, and test your instincts with the phishing awareness quiz.
Frequently asked questions
Do I need the email body?
No. Headers are enough. The tool ignores anything after the first blank line.
What does dmarc=fail with p=REJECT mean?
The domain owner has asked receivers to reject mail that fails DMARC, so a well-configured server would block it.
Is the Email Header Analyzer free?
Yes, the Email Header Analyzer is free. The first time you analyse your first headers, you are asked for your name and WhatsApp number once. After that, this and every other Uncodemy tool opens straight away without the form.