[Samba] Workaround for bind9 reload bug : samba_dlz Ignoring duplicate zone

[Prunk Dump]

Hi Samba Team !

First thank you all for your help !

Here some clarification on the problem.

-> The problem affect only my reverse zone "16.172.in-addr.arpa"
created with Samba. After the install, the zone contain only the PDC
reverse entry. So when bind9 in reloaded or reconfigured the "nslookup
172.16.0.30" command fail. When bind9 is restarted it works.

-> Here the bind9 logs. We see a "rndc reconfig" command that make
bind9 fail. (Full log in attachment).

-------------------
starting BIND 9.10.3-P4-Debian <id:ebd72b3> -f -u bind
...
Loading 'AD DNS Zone' using driver dlopen
samba_dlz: started for DN DC=lan,DC=lyc-guillaume-fichet,DC=ac-grenoble,DC=fr
samba_dlz: starting configure
samba_dlz: configured writeable zone 'lan.lyc-guillaume-fichet.ac-grenoble.fr'
samba_dlz: configured writeable zone '16.172.in-addr.arpa'
samba_dlz: configured writeable zone
'_msdcs.lan.lyc-guillaume-fichet.ac-grenoble.fr'
automatic empty zone: 10.IN-ADDR.ARPA
...
all zones loaded
running
received control channel command 'reconfig'
...
Loading 'AD DNS Zone' using driver dlopen
samba_dlz: starting configure
samba_dlz: Ignoring duplicate zone
'lan.lyc-guillaume-fichet.ac-grenoble.fr' from
'DC=@,DC=lan.lyc-guillaume-fichet.ac-grenoble.fr,CN=MicrosoftDNS,DC=DomainDnsZones,DC=lan,DC=lyc-guillaume-fichet,DC=ac-grenoble,DC=fr'
samba_dlz: Ignoring duplicate zone '16.172.in-addr.arpa' from
'DC=@,DC=16.172.in-addr.arpa,CN=MicrosoftDNS,DC=DomainDnsZones,DC=lan,DC=lyc-guillaume-fichet,DC=ac-grenoble,DC=fr'
samba_dlz: Ignoring duplicate zone
'_msdcs.lan.lyc-guillaume-fichet.ac-grenoble.fr' from
'DC=@,DC=_msdcs.lan.lyc-guillaume-fichet.ac-grenoble.fr,CN=MicrosoftDNS,DC=ForestDnsZones,DC=lan,DC=lyc-guillaume-fichet,DC=ac-grenoble,DC=fr'
automatic empty zone: 10.IN-ADDR.ARPA
...
zone 16.172.in-addr.arpa/NONE: (other) removed
...
zone lan.lyc-guillaume-fichet.ac-grenoble.fr/NONE: (other) removed
zone _msdcs.lan.lyc-guillaume-fichet.ac-grenoble.fr/NONE: (other) removed
reloading configuration succeeded
any newly configured zones are now loaded
samba_dlz: shutting down
-------------------

-> Using some wrapper script, I have found that this is systemd that
send the "rndc reconfig" command. But impossible to find in witch
script ( this is not systemd-networkd that is not started ).

--------------------
root at fichdc01:~# grep -r 'reconfig' /etc/init.d/
/etc/init.d/isc-dhcp-server:        echo "Run 'dpkg-reconfigure
isc-dhcp-server' to fix the problem."
root at fichdc01:~# grep -r 'reconfig' /lib/systemd/
Fichier binaire /lib/systemd/systemd-networkd correspondant
--------------------

-> Adding the "empty-zones-enable no;" option make the zone working !
But I still have the same logs in bind9. And the "samba_dlz: shutting
down" line ! I don't know if bind9 will work correctly.

--------------------
received control channel command 'reconfig'
...
Loading 'AD DNS Zone' using driver dlopen
samba_dlz: starting configure
samba_dlz: Ignoring duplicate zone
'lan.lyc-guillaume-fichet.ac-grenoble.fr' from
'DC=@,DC=lan.lyc-guillaume-fichet.ac-grenoble.fr,CN=Micr...
samba_dlz: Ignoring duplicate zone '16.172.in-addr.arpa' from
'DC=@,DC=16.172.in-addr.arpa,CN=MicrosoftDNS,DC=DomainDnsZones,DC=lan,DC=lyc..
samba_dlz: Ignoring duplicate zone
'_msdcs.lan.lyc-guillaume-fichet.ac-grenoble.fr' from
'DC=@,DC=_msdcs.lan.lyc-guillaume-fichet.ac-greno..
...
Mar 13 11:23:49 fichdc01 named[463]: zone 16.172.in-addr.arpa/NONE:
(other) removed
Mar 13 11:23:49 fichdc01 named[463]: zone
lan.lyc-guillaume-fichet.ac-grenoble.fr/NONE: (other) removed
Mar 13 11:23:49 fichdc01 named[463]: zone
_msdcs.lan.lyc-guillaume-fichet.ac-grenoble.fr/NONE: (other) removed
Mar 13 11:23:49 fichdc01 named[463]: reloading configuration succeeded
Mar 13 11:23:49 fichdc01 named[463]: any newly configured zones are now loaded
Mar 13 11:23:49 fichdc01 named[463]: samba_dlz: shutting down
--------------------

Thank again !

Baptiste.