I had done this maybe once before but I thought the functionality changed. Since it has not, through several exchange versions, I thought I would share the information I am likely to forget, yet again. When you add your user account to a mobile device, you “have” to enter the domain name when you add your account to the Exchange client application.
Well I was proved incorrect in my assumption this behavior couldn’t be changed. This is indeed a server side change that can allow you to just enter the user name.
So we have a few versions of IIS to cover but I will include the screen shots where Possible. First IIS 6.x with Exchange 2007. This is located in the Active Sync Virtual Directory properties:
Next we have IIS 7. In IIS 7 and 7.5 The default domain is automatically added if you use windows authentication. If you cant get the domain name to work with Iphone or other phone clients properly with Windows Authentication, you may have to use basic auth. for Basic authentication you can reference MS KB cc772009.
For Exchange 2013, The IIS Location is Inetmgr->Default Web Site->Owa-> enable Basic authentication. Then on the right pane (far right), you will see an edit button. Click that and enter the default domain:
That’s is. you should now be able to just enter the user name and be able to access you mobile account for Exchange Web Services.