1. Log into your Gmail or Googlemail Account
2. Open the Email whose headers you want to view
3. You will see Reply at the top right of the message pane.
3. You will see a little arrow pointing down next to Reply. Click on this down arrow next to Reply.
4. A drop down menu will open up. Select Show original in this menu
5. The full headers will now appear in a new window.
The ip should be in the header