Force Redirect (iRule)

Dear friends,

 

I have an application at the backend that gets used by the frontend portal. I have a situation where users are logging in fine using portal.f.com/gm. They land on the right application. However, when they search a document (.pdf/xls/docx/) and when they click to open, the header changes to actual host name from portal.f.com/gm to actualhost.f.com/gm...

 

How can I force it to not to switch so the hostname is hidden.

 

Your help is greatly appreciated!

 

Thanks, Afi