I have a similar setup, and I do it the way that Greg Choules suggests.
I could probably dig up the exact way I have BIND configured, but the
function is like this:
Clients query the non-AD BIND servers, for *all* queries. For the AD zone,
we use something like this; Our first level domain, lets assume is
example.com. All domain resources are in ad.example.com. So we configure
the non AD BIND servers to send queries for *.ad.example.com to the AD
servers.
So, in this way, the non-AD BIND servers handle all queries, but they
forward queries for ad.example,com to the AD name servers and return the
results.
I can't tell from the OP if they are using Samba or something else - but
we're using Samba in the example above. Samba has a couple of options for
their name server, an "internal" name server and a BIND version. Both can
be configured to forward any queries they aren't authoritative for to
another server. However, IIRC, at least the internal one can't handle large
loads. And while we'd probably be fine using it as our "primary" name
server, it seems needlessly risky.
I'd much rather have a well understood and mainstream BIND server as the
"front-line" server and then only forward queries for the AD zones to the
AD servers. (If you have some odd issue with a query outside the AD server
you can have a much larger support base, here, to help understand and fix
the issue.)
YMMV, but this was the way we decided to handle it after quite a bit of
consideration.
I hope that's helpful, though perhaps straying slightly off-topic for the
list.
On Thu, Jun 27, 2024 at 1:16 PM Greg Choules via bind-users <
bind-users@lists.isc.org> wrote:
> Hi Renzo.
> Ah OK, I had it the wrong way round. AD DNS needs to resolve names in the
> Internet on behalf of its clients, so it forwards to BIND.
>
> In that case, two questions:
> 1) What version of BIND are you running? You can get this with "named -V"
> 2) What is in the file "named.ca"?
> For a long time (which is why I need to know the version) BIND has had the
> Internet root hints built in, so you don't need a hint zone anymore. Unless
> you are defining different roots for some reason. Hence why I need to know
> the contents of that file.
>
> Thanks, Greg
>
>
>
> On Thu, 27 Jun 2024 at 18:06, Renzo Marengo <buckroger2...@gmail.com>
> wrote:
>
>>
>> Hi Greg,
>>
>> thank you very much for your explanation.
>>
>> Let’s supposte AD domain was ‘my domain.it’ and I have 6000 computers
>> of government institute.
>>
>> Here my bind configuration:
>>
>>
>> named.conf
>>
>> ———
>>
>> include “…. named.conf.options" ;
>>
>> zone "." IN {
>>
>> type hint;
>>
>> file "named.ca";
>>
>> };
>>
>> include “…. named.rfc1912.zones";
>>
>> include “…. named.root.key";
>>
>> ———
>>
>>
>>
>> named.conf.options
>>
>> ———
>>
>> logging {
>>
>> channel named_debug {
>>
>> syslog local6;
>>
>> severity debug 1;
>>
>> print-category yes;
>>
>> print-severity yes;
>>
>> print-time yes;
>>
>> };
>>
>> category default { named_debug; };
>>
>> };
>>
>>
>> options {
>>
>> auth-nxdomain no; # conform to RFC1035
>>
>> allow-recursion {127.0.0.1; A.B.C.D; dc1.mydomain.it; dc2.mydomain.it;
>> ….. } ;
>>
>> allow-query {127.0.0.1; A.B.C.D; dc1.mydomain.it; dc2.mydomain.it;
>> ….. } ;
>>
>> recursive-clients 3000;
>>
>> allow-query-cache {127.0.0.1; A.B.C.D; dc1.mydomain.it; dc2.mydomain.it;
>> ….. } ; ;
>>
>>
>> listen-on port 53 { 127.0.0.1; A.B.C.D; };
>>
>> directory “….. named";
>>
>> dump-file “….. cache_dump.db";
>>
>> statistics-file “….. named_stats.txt";
>>
>> memstatistics-file “…. named_mem_stats.txt";
>>
>> recursing-file “… named.recursing";
>>
>> secroots-file “… named.secroots";
>>
>> recursion yes;
>>
>> dnssec-enable no;
>>
>> dnssec-validation no;
>>
>>
>> bindkeys-file "….. named.iscdlv.key";
>>
>> managed-keys-directory "….. dynamic";
>>
>> pid-file "….. named.pid";
>>
>> session-keyfile "….. session.key";
>>
>> ———
>>
>>
>>
>> >Thirdly, I would not forward to AD DNS, unless the AD servers also
>> recurse and can provide >resolution for delegated names below the AD domain
>>
>> >that are not hosted on the AD servers themselves.
>>
>>
>> There is no forward option to AD DNS. Forward is enable from AD DNS to
>> A.B.C.D. bind9 server.
>>
>>
>>
>>
>> All clients are using AD DNS infact every query, about name of ‘
>> mydomain.it,’ is resolved from AD DNS.
>>
>> When client asks an external domain, e.g. www.google.it, AD server
>> forward query to A.B.C.D. server. (Forward option is set on every domain
>> controller)
>>
>> Only AD DNS make queries to A.B.C.D server and it’s necessary only to
>> solve external domains.
>>
>> A.B.C.D. server never makes queries to AD server. A.B.C.D. is next dns
>> server which partecipates when it’s necessary to resolve an external domain
>>
>>
>> I hope to have explained right.
>>
>> I thought A.B.C.D server made query to root server because into
>> configuration there is no reference to forward option, because I thought to
>> set as DNS forward a government dns of my country. What do you think?
>>
>> I have doubts about recursive and iterative queries options too.
>>
>> Thanks
>>
>>
>> Il giorno gio 27 giu 2024 alle ore 13:24 Greg Choules <
>> gregchoules+bindus...@googlemail.com> ha scritto:
>>
>>> Hi Renzo.
>>> Firstly, please can we see your BIND configuration and have the actual
>>> AD domain name.
>>>
>>> Secondly, BIND, or any other recursive DNS server, does not 'forward' to
>>> the root servers, unless you have configured it explicitly to do so, which
>>> would be a bad idea and not work anyway. It will recurse (paradoxically,
>>> perform non-recursive aka iterative queries) to the roots and other
>>> authoritative servers. It is an important distinction to be aware of.
>>>
>>> Thirdly, I would not forward to AD DNS, unless the AD servers also
>>> recurse and can provide resolution for delegated names below the AD domain
>>> that are not hosted on the AD servers themselves. Personally I would use a
>>> stub or static-stub zone in BIND to refer to the AD domain.
>>>
>>> In general, decide which DNS is going to do the resolving and make that
>>> the control point, fetching data from wherever it needs to (e.g. AD DNS) -
>>> using non-recursive queries - and using that data to construct answers for
>>> its clients.
>>>
>>> I hope that helps.
>>> Cheers, Greg
>>>
>>> On Thu, 27 Jun 2024 at 12:02, Renzo Marengo <buckroger2...@gmail.com>
>>> wrote:
>>>
>>>> I have Active Directory domain ( 'mydomain.it' ) with 8 domain
>>>> controllers to manage 8000 computers. Every Domain controller acts as dns
>>>> service and resolve internal domain names while forward queries about
>>>> external domains to another server, which Bind9 dns server (It's inside my
>>>> company)
>>>> I'm checking this Bind9 configuration (Centos server) and I see no
>>>> forward servers so I think It makes bind9 forward queries directly to root
>>>> servers. What do you think ?
>>>> According your opinion this Bind9 server should have to forward
>>>> requests to one or more dns server by forward option?
>>>>
>>>> --
>>>> Visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe
>>>> from this list
>>>>
>>>> ISC funds the development of this software with paid support
>>>> subscriptions. Contact us at https://www.isc.org/contact/ for more
>>>> information.
>>>>
>>>>
>>>> bind-users mailing list
>>>> bind-users@lists.isc.org
>>>> https://lists.isc.org/mailman/listinfo/bind-users
>>>>
>>> --
> Visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe
> from this list
>
> ISC funds the development of this software with paid support
> subscriptions. Contact us at https://www.isc.org/contact/ for more
> information.
>
>
> bind-users mailing list
> bind-users@lists.isc.org
> https://lists.isc.org/mailman/listinfo/bind-users
>
--
Visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from
this list
ISC funds the development of this software with paid support subscriptions.
Contact us at https://www.isc.org/contact/ for more information.
bind-users mailing list
bind-users@lists.isc.org
https://lists.isc.org/mailman/listinfo/bind-users
