View "Full Headers" of Gmail

Normally when you view an e-mail message in your inbox, it shows only the “From” address, the “To”address, the “Subject” line, and the date sent. The “full headers” can show more information aboutwhere the message was sent from and what path it travelled before reaching your inbox.

To View Full Header In Gmail Do The Following,
1. Open a e-mail message which you wish to see the Full header details.
2. In the below screenshot I blurred the Mail Address for Privacy reason.
3. In the upper right corner of the message, to the right of the word “Reply”, is a box with a downward-pointing arrow. And click the “Show original” option.



4. This will open up a new window displaying the full headers of the e-mail message.

What the full headers mean, and how to read them, is a much longer and more complicated answer.