The user types in the browser mysite.com, and the redirect is made to othersite.com/service.
I want the user to see mysite.com in the address bar and not othersite.com/service.
ie do the redirect but let mysite.com mask othersite.com/service.
is this possible in F5 with irule?
it certainly is possible in principle, there might be some things on your website that make it more or less dificult.
one thing to try is the proxy pass irule, as it is pretty much created for this