Once you have written a message and sent it, it is processed by the mail server at your ISP. If the message is addressed to someone who does not have a mailbox on your mail server, the mail server forwards the message to another mail server. The message is transmitted from one server to another. It can pass through multiple mail servers until it reaches the one on which the recipient of the message has a mailbox.

From the moment the message is created, information about it is added to a hidden section of the message, called the Internet header. These are technical details, for example, the author of the message, the software used to compose it, and the mail servers through which the message was passed to the recipient. This information can help you identify problems with the message or discover sources of unsolicited commercial mail.

Note:  The inclusion of erroneous information in message headers is a problem that tends to spread (we are also talking about spoofing). For example, a message may indicate that it comes from René Pelletier of Alpine Ski House ( [email protected] ) while it actually comes from a mass mailing service that extols the merits methods to get rich quickly. Therefore, before replying to a message to share your dissatisfaction with its sender, remember that it is possible that the header information has been falsified.

Find the Mail Headers in Outlook 2016, 2013 or 2010

  1. In an open email, click the File tab.
  2. On the Information tab, click Properties.

    The header information appears in the Internet Headers box.

Find the Mail Headers in Outlook 2007

  1. Open an email.
  2. On the Message tab, in the Options group, click the launcher of the dialog box.

    In the Message Options dialog box, the headers appear in the Internet Headers box.

That’s All.