The Samba AD DNS Back Ends: Difference between revisions

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__TOC__
=Internal DNS=


= Introduction =
Developing and using the DNS server built into Samba. AD backend.


In an Active Directory (AD), DNS is a very important service. It is used for:
==Status==
* name resolution
* locating services, such as Kerberos and LDAP
* locating local domain controllers (DC) when using AD sites. For details, see [[Active_Directory_Sites|Active Directory Sites]].


{{Imbox
Currently, the Samba DNS server implements RFC 1035 and RFC 2136. Work is currently under way to also support TSIG style signatures (RFC 2845) and GSS-TSIG for updates (RFC 3645).
| type = note
Also see the [[DNS/ToDo|Internal DNS ToDo list]].
| text = All clients and server in an AD must use a DNS server that is able to resolve the AD DNS zones.
}}


== Configuration ==


There are three options that can be added to smb.conf to control the behavior of DNS at this point:


# Allow unsigned updates | don't allow any updates | only allow signed updates
allow dns updates = True | False | Signed
# Query remote name servers on behalf of the clients
dns recursive queries = yes | no
# If recursive queries = yes is set, the following is also needed
dns forwarder = <ip addr of external dns server>


==Tests==


= Supported DNS Back Ends =
Run during make test
TDB_NO_FSYNC=1 make test TESTS=samba.tests.dns


Samba supports the following DNS back ends:
Run against external servers (Windows or BIND)
DC_SERVER_IP=<dns server ip> DC_SERVER=<dns server name> REALM=<dns server domain name part> PYTHONPATH=`pwd`/bin/python ./source4/scripting/bin/subunitrun samba.tests.dns


* [[Samba_Internal_DNS_Back_End|Samba Internal DNS Back End]]
=BIND 9.8.0 DLZ plug-in=
:* Default when provisioning a new domain, joining an existing domain or migrating an NT4 domain to AD.
:* No additional software or DNS knowledge is required.
:* Use this back end for simple DNS setups. For a list of limitations, see [[Samba_Internal_DNS_Back_End#Limitations|Limitations]].


* [[BIND9_DLZ_DNS_Back_End|BIND9_DLZ DNS Back End]]
Dynamically loaded zones plug-in for BIND 9.8.0. AD backend.
:* Requires BIND 9.8 or later installed and configured locally on the Samba Active Directory (AD) domain controller (DC). For additional information, see [[Setting_up_a_BIND_DNS_Server|Setting up a BIND DNS Server]].
:* Requires knowledge about the BIND DNS server and how to configure the service.
:* Use this back end for complex DNS scenarios, you can not configure in the internal DNS.


==Status==


If you are unsure which DNS back end to select during the DC installation, start with the Samba internal DNS. You can change the back end at any time. For details, see [[Changing_the_DNS_Back_End_of_a_Samba_AD_DC|Changing the DNS Back End of a Samba AD DC]].
Module is built with Samba, handles RFC 1035 and RFC 2136


=BIND & samba_dnsupdate=


{{Imbox
Non-AD backend, but works with older BINDs.
| type = important
| text = Do not use the <code>BIND9_FLATFILE</code> DNS back end. It is not supported and will be formally deprecated when 4.11.0 is released and removed at 4.12.0.
}}


==Status==


= Using the Samba Internal DNS Back End =
samba_dnsupdate script shipped with Samba, lets BIND handle DNS and just dynamically modifies AD-related information.

The Samba internal DNS server can be edited and queried using [https://www.samba.org/samba/docs/current/man-html/samba-tool.8.html samba-tool]. For example,

To get a get a list of zones: <code>samba-tool dns zonelist ''server''</code>

To update a record: <code>samba-tool dns update ''server'' ''zone_name'' A|AAA|CNAME|NS|MX|SRV|TXT ''old_value'' ''new_value''</code>

Run <code>samba-tool dns -h</code> to see the complete list of available commands.

= Selecting the AD Forest Root Domain =

Before you provision your Active Directory (AD), you must select a DNS zone for your AD forest root domain. For details, see [[Active_Directory_Naming_FAQ|Active Directory Naming FAQ]].

{{Imbox
| type = warning
| text = Samba does not support renaming the AD forest root domain.
}}

Best practices:

* Use a domain name you own.
* Use a subdomain of your domain, such as <code>ad.example.com</code>.
* Do not use <code>.local</code> domains. They can cause problems with Mac OS X and Zeroconf.

For details, see [[Active_Directory_Naming_FAQ|Active Directory Naming FAQ]].





----
[[Category:Active Directory]]
[[Category:DNS]]

Latest revision as of 18:10, 5 November 2021

Introduction

In an Active Directory (AD), DNS is a very important service. It is used for:

  • name resolution
  • locating services, such as Kerberos and LDAP
  • locating local domain controllers (DC) when using AD sites. For details, see Active Directory Sites.



Supported DNS Back Ends

Samba supports the following DNS back ends:

  • Default when provisioning a new domain, joining an existing domain or migrating an NT4 domain to AD.
  • No additional software or DNS knowledge is required.
  • Use this back end for simple DNS setups. For a list of limitations, see Limitations.
  • Requires BIND 9.8 or later installed and configured locally on the Samba Active Directory (AD) domain controller (DC). For additional information, see Setting up a BIND DNS Server.
  • Requires knowledge about the BIND DNS server and how to configure the service.
  • Use this back end for complex DNS scenarios, you can not configure in the internal DNS.


If you are unsure which DNS back end to select during the DC installation, start with the Samba internal DNS. You can change the back end at any time. For details, see Changing the DNS Back End of a Samba AD DC.



Using the Samba Internal DNS Back End

The Samba internal DNS server can be edited and queried using samba-tool. For example,

To get a get a list of zones: samba-tool dns zonelist server

To update a record: samba-tool dns update server zone_name A|AAA|CNAME|NS|MX|SRV|TXT old_value new_value

Run samba-tool dns -h to see the complete list of available commands.

Selecting the AD Forest Root Domain

Before you provision your Active Directory (AD), you must select a DNS zone for your AD forest root domain. For details, see Active Directory Naming FAQ.

Best practices:

  • Use a domain name you own.
  • Use a subdomain of your domain, such as ad.example.com.
  • Do not use .local domains. They can cause problems with Mac OS X and Zeroconf.

For details, see Active Directory Naming FAQ.