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

[Norbert Hanke]

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.