This question really relates to allowing to logon to a SharePoint installation from home but I guess it's a general IIS security question.

When the login box pops up to collect the windows credentials the user can just type in their user name on Safari/Chrome/FF and they can login correctly. On IE authentication fails as it seems to pass their local machine name by default and the user needs to replace this with domain\user. Not a big problem in some cases but we'd prefer it if the users didn't have to enter the domain name portion.

Is this simply a feature of IE that we can't control or is their something we can do with IIS/AD etc that will allow us to provide a default domain if one isn't specified?