preferred master

This boolean parameter controls if nmbd 8 is a preferred master browser for its workgroup.
If this is set to yes, on startup, nmbd will force an election, and it will have a slight advantage in winning the election. It is recommended that this parameter is used in conjunction with yes, so that nmbd can guarantee becoming a domain master.
Use this option with caution, because if there are several hosts (whether Samba servers, Windows 95 or NT) that are preferred master browsers on the same subnet, they will each periodically and continuously attempt to become the local master browser. This will result in unnecessary broadcast traffic and reduced browsing capabilities.

Supported on: At least Microsoft Windows 7 or Windows Server 2008 family

preferred master

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Samba\smb_conf\preferred master
Value Namepreferred master
Value TypeREG_SZ
Default Valueauto

samba.admx

Administrative Templates (Computers)