Windows names are not case sensitive, but UNIX names are case sensitive. The user names JSMITH, JSmith, and jsmith are equivalent names in Windows, but they are three distinct names in UNIX. Case sensitivity affects name mappings differently depending on the direction of the mapping.
For a Windows-to-UNIX mapping to produce a match, the case of the Windows user name must match the case of the UNIX user name. For example, only Windows user name "jsmith" matches UNIX user name "jsmith". Windows user name "Jsmith" does not match.
An exception to the case matching requirement for Windows-to-UNIX mappings occurs when the mapping uses the wildcard character "*" to map multiple user names.
If the identity mapping service encounters a mapping that maps Windows user *@some.domain to UNIX user "*", it first searches for a UNIX name that matches the Windows name exactly. If it does not find a match, the service converts the entire Windows name to lower case and searches again for a matching UNIX name. For example, the Windows user name "JSmith@some.domain" maps to UNIX user name "jsmith". If the service does not find a match after using lowercase for the Windows user name, the user does not obtain a mapping.
You can create a rule to match strings that differ only in case. For example, you can create a user-specific mapping to map the Windows user "JSmith@some.domain" to UNIX user "jSmith". Otherwise, the service assigns an ephemeral ID to the Windows user.
For a UNIX-to-Windows mapping to produce a match, the case does not have to match. For example, UNIX user name "jsmith" matches any Windows user name with the letters "JSMITH" regardless of case.