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://webmail.domain.com)
**domain.com to be replaced with your own domain name**
2) Once you have accessed to your Horde Inbox -> Double click on the desired email.
3) Then click on View Source on the top right pane of the popup window containing the e-mail content.
4) You are then able to view the complete email header of the email.