This article will show the steps on how you can view the complete email header in Horde Webmail
1) Login to Webmail using the URL (http://domainanme/webmail)
2) Select on Read Mail Using Horde
3) Double click on the email that you wish to view the header for
4) Then click on " View Source " on the top right pane
5) You are then able to view the complete email header of the email
This part will show the steps on how you can view the complete email header in Roundcube Webmail
1) Login to Webmail using the URL (http://domainanme/webmail)
2) Select on Read Mail Using RoundCube
3) Double click on the email that you wish to view the header for
4) Click on the option "More" → "Show Source"
5) You are then able to view the complete email header of the email