The remote host is using DidTheyReadIt to track when and where emails are read.
The remote host is using DidTheyReadIt to track when and where emails are read. This technology embeds a tiny link within an email. When the recipient opens the email, the link is retrieved from a xpostmail.com server and the original sender is notified when the image was read as well as the IP address of the recipient. This is done without the knowledge of the recipient.
Ensure that such activity is allowed according to corporate policies and guidelines.