[Samba] Samba internal dns problem / No domain service

[sr]

Hi,

I'm trying to move from a windows 2008R2 domain controler to samba4 ( 
centos 6.5 x64 + samba v 4.1.13 )
For now, both of server are working as AD controlers.

But I can't manage DNS from a windows client with the graphical tool... 
( it says "active directory not available, ..." )

On samba server if I try the following command
"samba-tool dns zonelist samba4.domain.com"

the following message appears
"9717, 'WERR_DNS_ERROR_DS_UNAVAILABLE"

and if I shutdown the win2008 server the message is "NT_STATUS_IO_TIMEOUT"

any help will be fully appreciate! :)
Thanks! :)

Samuel