All emails include information that can be used to trace the origin IP address of the email as well as its entire journey to your inbox. This information is typically hidden by default in most email clients, however you can find it in the full header of the email. Once you have accessed the full header, you can determine the original IP address of the computer that sent the message. There is absolutely nothing illegal about looking at information that is immediately available to you in email headers.
Adjust the email view settings on your specific email client so that you can see the full email header. As an example, in Microsoft Outlook double-click an email to open it in its own window, click "File" and then "Properties." The full email header text appears in the bottom of the Properties window.
Search through the email header, starting towards the bottom and going back to the top and look for lines in the email header with the text "Subject" or "Date."
Look at each line above the "Subject" or "Date" lines. You are looking for the first line you see that has any text similar to "Received from" or "X Received: from" or "X-Originating-IP." Look carefully, because it is easy to mistake a line with the text "Received by," which is not correct.
Locate the IP Address inside this first line you found with the text "Received from" or "X-Originating-IP." This is the IP address of the computer or device that sent the message.
Adjust the email view settings on your specific email client so that you can see the full email header. As an example, in Microsoft Outlook double-click an email to open it in its own window, click "File" and then "Properties." The full email header text appears in the bottom of the Properties window.
Search through the email header, starting towards the bottom and going back to the top and look for lines in the email header with the text "Subject" or "Date."
Look at each line above the "Subject" or "Date" lines. You are looking for the first line you see that has any text similar to "Received from" or "X Received: from" or "X-Originating-IP." Look carefully, because it is easy to mistake a line with the text "Received by," which is not correct.
Locate the IP Address inside this first line you found with the text "Received from" or "X-Originating-IP." This is the IP address of the computer or device that sent the message.