This week a client asked me to hide their Exchange OWA Login page and show the users a login prompt instead.
With Exchange 2010 this is possible and can be easily done.
To do, Open Exchange EMC -> Server Config -> Hub Server -> Select the Server -> Double Click Outlook Web App
In the below pic you will have the default settings after installation.
To have the prompt change the settings to:
Restart IIS from Service console or by typing iisreset /restart
When browsing to the OWA URL you will get the prompt.