Outlook 2010
- Open the Message in Outlook
- Click the File tab
- Select the Properties button
- Right-click in the Internet Headers box and choose Select All
- Right-click again in the Internet Headers box and choose Copy
- Paste that data into a reply to an email
Outlook 2003/2007
- Right-click the message and select Options
- Right-click in the Internet Headers box and choose Select All
- Right-click again in the Internet Headers box and choose Copy
- Paste that data into a reply to an email