Don't know whether this is known or has been fixed, already. I see a reproducible crash of samba-tool when querying DNS (DLZ setup). I have two different VMs. One called samba, which is the AD DC and another called samba4, which is my toy for client setup. Host samba4 cannot be resolved by DNS and it failed to add to the zone during the join - but this is a different issue. root at samba:/# samba-tool dns query samba ad.microsult.de @ A Password for [Administrator at AD.MICROSULT.DE]: Name=, Records=1, Children=0 A: 172.16.6.240 (flags=600000f0, serial=1, ttl=900) Name=_msdcs, Records=0, Children=0 Name=_sites, Records=0, Children=1 Name=_tcp, Records=0, Children=4 Name=_udp, Records=0, Children=2 Name=DomainDnsZones, Records=0, Children=2 Name=ForestDnsZones, Records=0, Children=2 Name=samba, Records=1, Children=0 A: 172.16.6.240 (flags=f0, serial=1, ttl=900) root at samba:/# samba-tool dns query samba4 ad.microsult.de @ A ERROR(runtime): uncaught exception - (-1073741772, 'NT_STATUS_OBJECT_NAME_NOT_FOUND') File "/usr/lib/python2.7/dist-packages/samba/netcmd/__init__.py", line 175, in _run return self.run(*args, **kwargs) File "/usr/lib/python2.7/dist-packages/samba/netcmd/dns.py", line 984, in run dns_conn = dns_connect(server, self.lp, self.creds) File "/usr/lib/python2.7/dist-packages/samba/netcmd/dns.py", line 37, in dns_connect dns_conn = dnsserver.dnsserver(binding_str, lp, creds) root at samba:/# samba-tool --version 4.1.7-Debian Just for informing the developers, - lars.