[Samba] magic user mapping

[Kevin Field]

Hi,

Samba 4.0.9 on CentOS 6.4 serving Windows XP clients here.  I still 
haven't sat down and figured out Windows-RID-to-unix-ID maps yet. 
However, I noticed that I can put a person's lowercased name in a 'valid 
users' list for a share and it works, even though they don't have a unix 
account.  But doing this for lowercased custom group names (we have a 
'MYDOM\Supervisors' group, so I tried @supervisors or supervisors) 
didn't seem to have any effect.  Why is that?

I also tried to figure out the unix ID that that group maps to by taking 
a test file in Windows and going to the Advanced part of security and 
changing the owner to MYDOM\Supervisors.  In ls -l on CentOS it shows up 
as 3000014.  So I tried 3000014 with or without @ in front of it in 
'valid users' for a share, but to no effect.  That I understand even 
less.  :)

Thanks for any illumination here,
Kev