[Samba] Problems attaching Windows server as secondary DC.

[simon+samba at matthews.eu]

I have my Samba4 up and running. I was able to get a Windows 2012 server 
to join the samba4 domain.

However, I have not been able to get the Windows server to promote itself 
to a secondary DC.

I would appreciate any suggestions on debugging this issue.

One the Server 2012 machine, in the "prerequisites check", I see the 
following message:
"Verification or prerequisites for Active Directory preparation failed 
......
Exception: THe RPC server is unavailable. ....."
Adprep could not retrieve data from the server <servername> ..."

The servername is correct and resolves to my samba4 server.

On the Samba4 server, I see the following in the logs:
[2013/04/12 12:02:30,  3] 
../auth/ntlmssp/ntlmssp_util.c:34(debug_ntlmssp_flags)
   Got NTLMSSP neg_flags=0xe2088235
[2013/04/12 12:02:30,  3] 
../source4/rpc_server/dcerpc_server.c:961(dcesrv_request)
   Warning: 60 extra bytes in incoming RPC request
[2013/04/12 12:02:30,  3] 
../source4/rpc_server/drsuapi/dcesrv_drsuapi.c:74(dcesrv_drsuapi_DsBind)
   ../source4/rpc_server/drsuapi/dcesrv_drsuapi.c:74: doing DsBind with 
system_session
[2013/04/12 12:02:33,  3] 
../source4/smbd/service_stream.c:63(stream_terminate_connection)
   Terminating connection - 'NT_STATUS_CONNECTION_DISCONNECTED'
[2013/04/12 12:02:33,  3] 
../source4/smbd/process_single.c:114(single_terminate)
   single_terminate: reason[NT_STATUS_CONNECTION_DISCONNECTED]


Any ideas?
Simon