[Samba] samba 4.4.5 DC with bind9: DNS update failing with NOTAUTH

[Norbert Hanke]

On 18.07.2016 23:13, Rowland penny wrote:
> On 18/07/16 21:31, Norbert Hanke wrote:
>> On 18.07.2016 20:10, Rowland penny wrote:
>>> On 18/07/16 00:02, Norbert Hanke wrote:
>>>> Hello,
>>>>
>>>> I'm trying to join a samba 4 DC to an already existing samba 4 DC, 
>>>> both with BIND9_DLZ. Samba is at version 4.4.5, bind is version 
>>>> 9.10.4-P1, all brand new.
>>>>
>>>> The existing DC runs fine, but the added DC refuses to update its 
>>>> local bind database: every attempt to update the local DNS results 
>>>> in "update failed: NOTAUTH". AD replication works perfectly.
>>>>
>>>> Both systems are set up identically except for the 
>>>> provisioning/joining command. On the first I did
>>>> samba-tool domain provision --use-rfc2307 --domain=$domain 
>>>> --server-role=dc --dns-backend=BIND9_DLZ \
>>>>  --realm=$realm --adminpass=Wonttell
>>>> and on the second I do
>>>> samba-tool domain join $domain DC -Uadministrator --realm=$realm 
>>>> --dns-backend=BIND9_DLZ
>>>>
>>>> Versions are the same, bind config is the same, I tried follow 
>>>> every rule I could find.
>>>>
>>>> # samba_dnsupdate --verbose -d 9
>>>> INFO: Current debug levels:
>>>>   all: 9
>>>> (... more such levels ...)
>>>> lpcfg_load: refreshing parameters from /usr/local/samba/etc/smb.conf
>>>> Processing section "[global]"
>>>> Processing section "[netlogon]"
>>>> Processing section "[sysvol]"
>>>> pm_process() returned Yes
>>>> added interface eth0 ip=192.168.1.9 bcast=192.168.1.255 
>>>> netmask=255.255.255.0
>>>> IPs: ['192.168.1.9']
>>>> Module 'tombstone_reanimate' is disabled. Skip 
>>>> registration.lpcfg_servicenumber: couldn't find ldb
>>>> schema_fsmo_init: we are master[no] updates allowed[no]
>>>> schema_fsmo_init: we are master[no] updates allowed[no]
>>>> Looking for DNS entry A dc2.ad.domain.ch 192.168.1.9 as 
>>>> dc2.ad.domain.ch.
>>>> Looking for DNS entry A ad.domain.ch 192.168.1.9 as ad.domain.ch.
>>>> Failed to find matching DNS entry A ad.domain.ch 192.168.1.9
>>>> need update: A ad.domain.ch 192.168.1.9
>>>> (... many more such Looking...need update blocks)
>>>> 24 DNS updates and 0 DNS deletes needed
>>>> ldb_wrap open of secrets.ldb
>>>> Received smb_krb5 packet of length 298
>>>> Received smb_krb5 packet of length 1311
>>>> update(nsupdate): A ad.domain.tld 192.168.1.9
>>>> Calling nsupdate for A ad.domain.tld 192.168.1.9 (add)
>>>> Outgoing update query:
>>>> ;; ->>HEADER<<- opcode: UPDATE, status: NOERROR, id:      0
>>>> ;; flags:; ZONE: 0, PREREQ: 0, UPDATE: 0, ADDITIONAL: 0
>>>> ;; UPDATE SECTION:
>>>> ad.domain.tld.        900     IN      A       192.168.1.9
>>>>
>>>> update failed: NOTAUTH
>>>> Failed nsupdate: 2
>>>> (... many more such failed updates ...)
>>>> Failed update of 24 entries
>>>> # 22:37:30 root at dc2:/root/
>>>>
>>>>
>>>> In /var/log/syslog there are these equivalent 24 error message 
>>>> every 10 minutes:
>>>> Jul 17 22:52:06 dc2 samba[3960]: [2016/07/17 22:52:06.742592, 0] 
>>>> ../lib/util/util_runcmd.c:328(samba_runcmd_io_handler)
>>>> Jul 17 22:52:06 dc2 samba[3960]: 
>>>> /usr/local/samba/sbin/samba_dnsupdate: update failed: NOTAUTH
>>>> and the last of the 24 entries is always followed by
>>>> Jul 17 22:52:06 dc2 samba[3960]: [2016/07/17 22:52:06.866877, 0] 
>>>> ../source4/dsdb/dns/dns_update.c:295(dnsupdate_nameupdate_done)
>>>> Jul 17 22:52:06 dc2 samba[3960]: 
>>>> ../source4/dsdb/dns/dns_update.c:295: Failed DNS update - 
>>>> NT_STATUS_TOO_MANY_OPENED_FILES
>>>>
>>>> smb.conf is minimalistic:
>>>>
>>>> # Global parameters
>>>> [global]
>>>>         netbios name = DC2
>>>>         realm = AD.DOMAIN.TLD
>>>>         server services = s3fs, rpc, nbt, wrepl, ldap, cldap, kdc, 
>>>> drepl, winbindd, ntp_signd, kcc, dnsupdate
>>>>         workgroup = DOMAIN
>>>>         server role = active directory domain controller
>>>>
>>>> [netlogon]
>>>>         path = /usr/local/samba/var/locks/sysvol/ad.domain.tld/scripts
>>>>         read only = No
>>>>
>>>> [sysvol]
>>>>         path = /usr/local/samba/var/locks/sysvol
>>>>         read only = No
>>>>
>>>> Maybe somebody has an idea what I did wrong?
>>>>
>>>>
>>>>
>>>
>>> Try reading this wiki page, it may help:
>>>
>>> https://wiki.samba.org/index.php/Check_and_fix_DNS_entries_on_DC_joins
>>>
>>> Rowland
>>>
>>>
>> Yes I did that from the begining. The entries were indeed missing and 
>> added them.
>>
>> I also tried adding with a lower-case dc2 instead of DC2. It did not 
>> make a difference.
>>
>> But now it surprises me that adding worked at all. Isn't a 
>> "*samba-tool dns add ..." about the same as what **samba_dnsupdate 
>> does when adding entries?*
>>
>> *And I just checked: the two added entries are still there and are 
>> resolvable through both DNS servers.* It's a mystery to me.
>>
>>
>
> Try adding 'allow dns updates = nonsecure and secure' to your smb.conf 
> files.
> I would also check that it isn't something like apparmor or selinux 
> blocking the updates.
>
> If I run the same command on my second DC, at the point it goes wrong 
> for you, I get:
>
> Looking for DNS entry A dc2.samdom.example.com 192.168.0.6 as 
> dc2.samdom.example.com.
> Looking for DNS entry A samdom.example.com 192.168.0.6 as 
> samdom.example.com.
> Looking for DNS entry SRV _ldap._tcp.samdom.example.com 
> dc2.samdom.example.com 389 as _ldap._tcp.samdom.example.com.
>
> From your output, it looks as if it cannot find the 'A' record for 
> your second DC.
>
> Rowland
>
>
>
I added the smb.conf entry , rebooted: no change. This is on a plain 
vanilla raspberry pi system without apparmor or selinux configured. The 
first DC dc1 is on an indentical setup and works.

I check dc2: The A record of dc2 is known to both DNS servers.

But the A record for the domain alone (without the dc2) and the SRV 
record for _ldap... both point to the IP of dc1, on both DNS servers. 
Could that be the problem?