To view the full mail headers, open the corresponding message, and follow the instructions below:

Webmail Classic:

  • Click on the Show headers button.

Roundcube:

  • Click on the Details link.
  • Click on the All headers... link.

Outlook Express:

  • On the File menu, click Properties.
  • Click the tab labeled Details.

Thunderbird:

  • On the View menu, click Message Source.

Entourage:

  • On the View menu, click Options.
  • Click the section labeled Internet Headers.

Microsoft Outlook 2003:

  • On the View menu, click Options.
  • Click the section labeled Internet Headers.

Microsoft Outlook 2007:

  • On the Options menu, click Internet Headers.

Microsoft Outlook 2010:

  • Click on File -> Info -> Properties.
  • On the Properties window, locate the Internet headers box.

Mail for Mac:

  • On the View menu, click Message.
  • Click All Headers.

Windows Mail:

  • On the File menu, click Properties.
  • Click the tab labeled Details.

Windows Live Mail:

  • Right-click the message and click View source.

Gmail:

  • Click the More button in the top right corner (three vertically aligned dots) > Show original.

Hotmail.com / Outlook.com / Live.com:

  • Click the More actions button in the top right corner of the message (three horizontally aligned dots) > View > View message source.

Yahoo Mail:

  • Click the More button at the top of the message (three horizontally aligned dots) > View raw message.