Join Win7 to Samba

[Piotr Zacharzewski]

Hello,
I have a problem with join Windows 7 client to Samba domain
I have 1 domain with two domain controllers A,B
DC Config:
A:samba35-3.5.11
smb.conf
 preferred master = yes
 domain master = yes

B:samba-3.3.9
 domain master = no
 preferred master = no

When i want to check witch DC is PDC (windows cmd: "nltest
/dclist:<domain>")
I get:
List of DCs in Domain zetis
    \\B (PDC)
    \\A

Why server B is mark as PDC?

-- 
Piotr Zacharzewski