How to View Full Message Headers in Mozilla Thunderbird

This article explains how to reveal headers that are normally hidden in emails in Mozilla Thunderbird. The header can help you troubleshoot email problems.

How to View Hidden Mozilla Email Header Data

All emails consist of two parts: the header and the body. The standard header—which is the part you normally see—typically lists the sender and recipient of the message, date, and subject. Behind the scenes, though, the header contains much more information, such as the path it took from sender to recipient, the sender's IP address, and the message's priority. This information isn't particularly easy to interpret and isn't usually of interest to the recipient, so it's hidden.

When you're asked to pass along all message headers to thwart a spammer or troubleshoot an email problem, or if you're simply curious, you can reveal all the hidden info.

1. Open Thunderbird.

2. Click a message in the reading pane to open it in a new tab or window.

3. Select View > Headers > All from the menu bar to display the full message headers.

4. To return to the standard set of headers, select View > Headers > Normal from the menu.

Viewing a Message's Source

If you want to see or need to copy the header lines in their original unformatted state, open the message's source in Mozilla Thunderbird by selecting View > Message Source. The source code is more extensive than just headers and includes the coding for the entire email.