Basic Authentication Domain
Users logging on with the Basic authentication method must belong to a specific domain. A domain is a computer or a network of computers managed as a single administrative entity. You can configure your Web server to assume that all users who do not explicitly specify their domain, belong to a default domain. For example, if a userÆs account is on a domain called Sales and that user logs on as JeffSmith, without specifying the domain (that is, logging on as Sales\JeffSmith), your Web server assumes that the user belongs to the Sales domain.
If your Web server does not belong to a network, then the default domain is the name of your computer.