Display Email User Agent In Thunderbird

Thunderbird users can take a look at the email headers to find out lots of information about the email sender. This includes content types, dates and the servers the email was send from. Many Thunderbird users do not know that it is possible to add the user agent to the header display in the email client.

The user agent tells them the program or service that was used to send the email which can help evaluate the validity of the email. It should be noted however that the user agent is not always displayed.

It might raise suspicion for instance if a user has send emails from a specific program in the past while the latest email uses a different service or program.

Thunderbird users who want to add the user agent to the header information in the email software need to perform the following steps:

• Access the Options by clicking on Tools > Options in the header menu of Thunderbird.
• Switch to the Advanced tab and click on Config Editor, accept the warning message.
• Filter for the parameter mailnews.headers.showUserAgent
• Double-click the parameter to set it to true
• A restart might be required before the information are displayed.

The changes can be reverted by performing the same steps again. Do you have Thunderbird tips of your own? Let us hear them in the comments.

Related Articles:

Author: Martin Brinkmann, Wednesday April 7, 2010 -
Tags:email headers, thunderbird, thunderbird tips, user agent

Responses so far:

1. Mike says:

   April 7, 2010 at 11:40 pm

   I just use “Display Mail User Agent” extension to adds an image on the right side of the “header view” which displays the icon of the application with which the selected mail was written.

   https://addons.mozilla.org/en-US/thunderbird/addon/562

   Reply
2. Sonohuey says:

   April 8, 2010 at 1:52 pm

   Thanks for this story. This is a an exceptionally handy thing to turn on.

   Thanks again

   Reply