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

[Rowland penny]

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