Remote Content in Messages

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  • Revision id: 107259
  • Created:
  • Creator: Lan
  • Comment: Some improvements
  • Reviewed: No
  • Ready for localization: No
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Email messages can contain remote content such as images or stylesheets. To protect your privacy, Thunderbird does not load remote content automatically, but instead shows a notification bar that it blocked remote content.

What is remote content and why is it blocked?

Remote content are parts of a message (such as images, stylesheets, or videos) which are not included in the message itself, but are downloaded from the Internet when you view the message.

Remote content is a privacy concern because it allows the message sender to know:

  • each time you view the message
  • rough details about what application and what platform you are using
  • your current geographic location (a rough approximation by IP address)
  • that your email address is actually used ("alive")

This is almost the same information web sites commonly collect about you during normal web surfing. While browsing has the same privacy implications, what makes remote content in messages different is that it is targeted at you initially, so you can assume your access is directly linkable to your email address. This is also why spam often contains remote images (also known as "web bugs") which allow the spammer to mark your address as valid if the image is ever loaded.

On the other hand, if you do get many genuine emails containing remote content, it can get annoying having to click "Show remote content in this message" for each message. Emails look much better with images and stylesheets turned on.

All in all, however, what you do online in a web browser is usually disclosing much more information about yourself than loading content in an email message.

To protect your privacy, Thunderbird has blocked remote content in this message

Remote content blocked

This is the default, and what most people should be using. In this mode, Thunderbird will show a blocked remote content notification bar when content is blocked.

Display remote content for a particular message, sender or domain

Remote content blocking options Win Remote content blocking options

From the notification bar, you can choose to:

  • Show remote content in this message to show remote content just for this particular message, OR
  • Edit remote content optionspreferences to display remote content by default (see next section), OR
  • Allow remote content for <e-mail address> to show the remote content for all messages from this sender.
  • Allow remote content for <domain> to show the remote content stored on this domain.

Allow remote content for… adds the sender email address or sites (currently blocked in the message) to the remote content whitelist.

Note however, that email addresses are easily spoofable in contrast to web sites that serve remote content. As long as the network is not compromised, it is much more difficult to spoof content than email addresses.

Display remote content by default

If you are willing to accept the privacy implications of displaying remote content for all messages, Thunderbird allows you to display remote content by default. To set it so:

  • At the top of the Thunderbird window, click the Tools menu (Alt + T) and select Options…OptionsIn the menu bar, click the Thunderbird menu and select PreferencesAt the top of the Thunderbird window, click the Edit menu and select Preferences, or click the Application menu button New Fx Menu and choose Options…OptionsPreferences.
  • Select the Privacy panel.
  • If the Allow remote content in messages checkbox is ticked, all remote content will be loaded, just like it would in a browser. You can exclude specific sites from the rule by clicking Exceptions… and adding the domain or email address.