How to Locate your Email Headers
Dependent on your email service, follow the instructions below to uncover the email headers:
Right click on your desired email and click “Show Original”.
Zimbra Desktop Application
Right click on the email and scroll to “Show Original”.
*If the option to “Show Original” is greyed out, click to expand the email thread and select an individual email.
Outlook.com / Windows Live Mail
Right click the desired message and click to “View Message Source”
Mail for Mac OS X
Right click on the desired message and up in the top menu go to: VIew > Message > All Headers.