This option helps Samba to try and 'guess' at the real UNIX username, as many DOS clients send an all-uppercase username. By default Samba tries all lowercase, followed by the username with the first letter capitalized, and fails if the username is not found on the UNIX machine. If this parameter is set to non-zero the behavior changes. This parameter is a number that specifies the number of uppercase combinations to try while trying to determine the UNIX user name. The higher the number the more combinations will be tried, but the slower the discovery of usernames will be. Use this parameter when you have strange usernames on your UNIX machine, such as AstrangeUser . This parameter is needed only on UNIX systems that have case sensitive usernames. 0 5