[Samba] several dns issues after switching fsmo roles to samba-dc

[Alex]

Hello Rowland,

>> 3. I see the errors in the System log on the former DC (vm-dc1), like:
>> The dynamic registration of the DNS record '_ldap._tcp.DomainDnsZones.domain.com. 600 IN SRV 0 100 389 vm-dc1.domain.com.' failed on the following DNS server:
>>
>> DNS server IP address: 172.26.1.83
>> Returned Response Code (RCODE): 0
>> Returned Status Code: 9016
>> ...
>> ADDITIONAL DATA
>> Error Value: DNS signature failed to verify.
>>
>> (172.26.1.83 is the new PDC - vm-dc3)

> Interesting, if it is in a log on a windows PC, then it is likely that 
> it is the windows DC trying to update the record, which it shouldn't and 
> will fail if vm-dc3 already has updated it.

Indeed,  the  Windows  DC tried to update the record.. The other day, I've found
that  the  record is just missing (expired?). So, I've started to dig in and was
able to resolve the issue in this way:
1. I could reproduce the issue by restarting NETLOGON service on the Windows DC.
Also the following commands failed with "Connection Status = 1311 0x51f
ERROR_NO_LOGON_SERVERS":
nltest.exe /dsregdn
nltest /query
2. After some googling, I've found the fixing command:
nltest /sc_reset:domain.com

After   that,  all  vm-dc1  records  were  registered  in  the  AD  w/o  issues
using "nltest.exe /dsregdn" command.
Unfortunately, it's failing again after restarting NETLOGON service.

-- 
Best regards,
Alex