|Scenario Task Description=The short answer is: you can't. You can only be certain of the sender's identity and for that you need to read [[I want to learn about digital signatures]]. There are however some tips to help you better understand where the email ''may'' have come from.
Every email you receive is made up of several components. There is the content itself, address details, as well as technical data about the message - also known as the message header. It contains detailed information generated by your email server about where the message came from and how it was processed before arriving in your inbox. This may be your only forensic clue to investigate the message's origin. To If you want to learn more about how to read a message headerexamine email headers, read this guide on [https://learn.equalit.ie/wiki/Email_spoofing email spoofing] and [https://support.google.com/mail/answer/29436?hl=en Gmail's guide] on understanding their message headers.
You can also copy and paste the message header into the [http://mxtoolbox.com/EmailHeaders.aspx MXToolbox] to get a humanly readable context of where this email has been.
}}