When logging on to my exchange 2007 server OWA, I need to enter "domain\username", I want to be able to log in by using "username" alone.
So here is how I did that:
Open Exchange Management Console, expand Server Configuration and find Outlook Web Access tab in Client Access. Double click "OWA (Default Web Site)" and go to Authentication tab. Uncheck "Integrated Windows authentication" box (screenshot) and click OK.
Open your webmail and try to log in without specifying a "domain\" in your User Name.