История изменений

включаешь дебаг и смотришь на процесс выбора MB, делаешь выводы на его основе.

Затем набираешь man smb.conf и читаешь:

os level (G)

This integer value controls what level Samba advertises itself as
for browse elections. The value of this parameter determines
whether nmbd(8) has a chance of becoming a local master browser for
the workgroup in the local broadcast area.

Note: By default, Samba will win a local master browsing election
over all Microsoft operating systems except a Windows NT 4.0/2000
Domain Controller. This means that a misconfigured Samba host can
effectively isolate a subnet for browsing purposes. This parameter
is largely auto-configured in the Samba-3 release series and it is
seldom necessary to manually override the default setting. Please
refer to the chapter on Network Browsing in the Samba-3 HOWTO
document for further information regarding the use of this
parameter. Note: The maximum value for this parameter is 255.

Затем действуешь в соответствии с прочитанным и понятым.

включаешь дебаг и смотришь на процесс выбора MB, делаешь выводы на его основе.

Затем набираешь man smb.conf и читаешь:

os level (G)

This integer value controls what level Samba advertises itself as
for browse elections. The value of this parameter determines
whether nmbd(8) has a chance of becoming a local master browser for
the workgroup in the local broadcast area.

Note: By default, Samba will win a local master browsing election
over all Microsoft operating systems except a Windows NT 4.0/2000
Domain Controller. This means that a misconfigured Samba host can
effectively isolate a subnet for browsing purposes. This parameter
is largely auto-configured in the Samba-3 release series and it is
seldom necessary to manually override the default setting. Please
refer to the chapter on Network Browsing in the Samba-3 HOWTO
document for further information regarding the use of this
parameter. Note: The maximum value for this parameter is 255.