無料メールヘッダー解析ツール

フィッシングを見抜くためのメールヘッダーの分析

メールヘッダーは、すべてのメッセージの真の発信元を明らかにします。. 下にメールヘッダーを貼り付けて、SPF、DKIM、DMARC認証を確認し、メッセージのルートを追跡し、フィッシングやなりすましの試みを示す可能性のある警告を特定します。すべての分析はブラウザ内で行われます。.

How to get the raw email headers

The tool needs the full raw headers, not the visible message. In Gmail, open the email, click the three-dot menu and choose “Show original”. In Outlook, open the message, go to File then Properties, and copy the “Internet headers” box. In Apple Mail, use View then Message then Raw Source. Paste the whole block above.

What the results tell you

Headers record the path a message actually took and the results of the checks that prove who sent it. Focus on three: SPF (was the sending server authorised for that domain), DKIM (was the message cryptographically signed and unaltered), and DMARC (did the visible “From” line align with those checks). A “fail” or “none” on these, especially when the email asks for money, credentials, or urgency, is a strong spoofing signal. Our guide to email header red flags walks through real examples.

Browse the rest of our free security tools for password and file-integrity checks.

よくある質問

What are SPF, DKIM and DMARC?

They are email authentication checks. SPF verifies the sending server is authorised for the domain, DKIM verifies the message was signed and not altered, and DMARC ties both to the visible “From” address. Failures on these are common signs of spoofing.

Can headers prove an email is a scam?

They are strong evidence, not absolute proof. Failed authentication plus a suspicious request is a clear red flag, but a message can pass these checks and still be malicious if the sender’s own account was compromised. Combine the headers with judgement about what the email is asking for.