Setting up a BIND DNS Server: Difference between revisions

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= Introduction =
= Introduction =


If you are planning to set up a Samba Active Directory (AD) domain controller (DC) using the <code>BIND9_DLZ</code> back end, you have to install and configure the BIND DNS server first.
This HowTo describes how to compile and configure a basic BIND installation, that can be used as Samba DC DNS backend. Skip this guide if you already have an existing BIND installation that can be used as a Samba AD backend.


The following describes how to set up a basic BIND installation you can use as Samba AD DC back end.
If you need to setup a more complex DNS setup than what is possible with the Samba 4 internal DNS, then using BIND as the DNS backend is recommended.

{{Imbox
| type = important
| text = Samba AD is not compatible with other DNS servers, even if those that supports tkey-gss updates, because parts of Samba (like the DNS management RPC server and the domain join) assume the replicated DNS entries in the AD Database are the same as those exposed over DNS. Likewise the security of the system depends on the ACLs on each DNS entry in AD.
}}

{{Imbox
| type = note
| text = If you are changing from the internal dns server to a Bind9 dns server, you will also need to read [[Changing_the_DNS_Back_End_of_a_Samba_AD_DC|Changing_the_DNS_Back_End_of_a_Samba_AD_DC]].
}}




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= Installing BIND =
= Installing BIND =


For a list of supported BIND versions, see [[BIND9_DLZ_DNS_Back_End#Configuring_the_BIND9_DLZ_Module|Configuring the BIND9_DLZ module]].
The use of BIND as a backend for your Samba Active Directory Domain Controller is currently only supported in versions 9.8 and 9.9. Users of bind 9.7 are strongly encouraged to upgrade! If this is not possible, refer to the section [[BIND9_DLZ_DNS_Back_End#BIND_9.7_2|DNS dynamic updates via Kerberos for BIND 9.7]] for instructions on configuring BIND 9.7.

{{Imbox
| type = note
| text = You can not run BIND in a changed root environment (chroot), because the <code>BIND9_DLZ</code> must be able to access the Samba Active Directory (AD) database files directly.
}}



== Package Installation ==

Installing BIND using packages provided with your distribution is the recommended way. Select this installation mode for an easy installation and to automatically receive updates when available. For details how to install packages, see the distribution's package manager documentation.

Make sure that your package provider compiled BIND using the following options:
* <code>--with-gssapi=yes</code> or <code>--with-gssapi=/usr</code> (or similar) for secure dynamic DNS updates using Kerberos
* <code>--with-dlopen</code> dynamically loadable zones (DLZ)

{{Imbox
| type = note
| text = Later versions of Bind9.9.x have the <code>--with-dlopen</code> option builtin and is not shown by the following command. This happened around Bind 9.9.4
}}

To list the build options:
# named -V
BIND 9.x.y built with ... '--with-dlopen=yes' '--with-gssapi=yes' ...





== Compiling and Installing BIND ==
If you install BIND from the repositories of your distribution, you can skip the following two steps, but make sure that it was compiled with the '--with-gssapi' and '--with-dlopen' options (see below) before using it as the Samba AD DNS backend.


Use this installation mode if you are an advanced user and know how to compile software.




== Downloading ==
=== Downloading the Sources ===


Download your desired and Samba 4 supported version from [https://www.isc.org/software/bind https://www.isc.org/software/bind].
Download a supported BIND version from https://www.isc.org/software/bind.






== Compiling BIND ==
=== Compiling BIND ===


To use BIND 9.8.1 or later as Samba AD backend, at least the following two configure options are required:
* Pass at least the following parameters to the <code>configure</code> command:


# ./configure --with-gssapi=/usr/include/gssapi --with-dlopen=yes
# ./configure --with-gssapi=/usr/include/gssapi --with-dlopen=yes


: Add further parameters, if required.
Please check if there are other options you require for your environment. If you are building BIND 9.8.0, you must use '--with-dlz-dlopen=yes' instead of '--with-dlopen=yes'.


To build and install:
* To build and install, run:


# make
# make
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=== Adding a User and Group for BIND ===
= Configuration =


For security reasons, do not run BIND as <code>root</code> user.
== Setting up a basic named.conf ==


To create a <code>named</code> group using GID <code>25</code>:
The following example is a basic 'named.conf' for a pure minimal BIND installation without any Samba AD parts. See [[BIND9_DLZ_DNS_Back_End|here]] for how to configure Bind for Samba AD.


# /etc/named.conf
# groupadd -g 25 named

# Global BIND configuration options
To create a <code>named</code> account with UID <code>25</code>, primary group <code>named</code>, home directory <code>/var/named/</code>, and without a valid shell:

# useradd -u 25 -g named -d /var/named -M -s /sbin/nologin named

For details, see the <code>useradd (8)</code> and <code>groupadd (8)</code> man page.





= Configuring BIND =

== Setting up a named.conf file ==

To locate the directory, BIND uses to read the <code>named.conf</code> file:

# named -V
BIND 9.x.y built with ... '--sysconfdir=/etc' ...

In the previous example, BIND reads the configuration from the <code>/etc/named.conf</code> file.

The following is a basic configuration file:

# Global Configuration Options
options {
options {
Line 54: Line 115:
empty-zones-enable no;
empty-zones-enable no;
# IP addresses and network ranges allowed to query the DNS server:
allow-query {
allow-query {
127.0.0.1;
127.0.0.1;
10.1.1.0/24;
10.99.1.0/24;
# add other networks you want to allow to query your DNS
};
};
# IP addresses and network ranges allowed to run recursive queries:
# (Zones not served by this DNS server)
allow-recursion {
allow-recursion {
127.0.0.1;
10.1.1.0/24;
10.1.1.0/24;
# add other networks you want to allow to do recursive queries
};
};
# Forward queries that can not be answered from own zones
# to these DNS servers:
forwarders {
forwarders {
# Google public DNS server here - replace with your own if necessary
8.8.8.8;
8.8.8.8;
8.8.4.4;
8.8.4.4;
};
};
# Disable zone transfers
allow-transfer {
allow-transfer {
# this config is for a single master DNS server
none;
none;
};
};
};
# Root Servers
};
# (Required for recursive DNS queries)
# Root servers (required zone for recursive queries)
zone "." {
zone "." {
type hint;
type hint;
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};
};
# Required localhost forward-/reverse zones
# localhost zone
zone "localhost" {
zone "localhost" {
type master;
type master;
Line 91: Line 154:
};
};
# 127.0.0. zone.
zone "0.0.127.in-addr.arpa" {
zone "0.0.127.in-addr.arpa" {
type master;
type master;
Line 96: Line 160:
};
};


For details about the used parameters and options, see the <code>named.conf (5)</code> man page.
We chose '/var/named' as directory in 'named.conf' to be the place where our zonefiles, etc. reside. If you want to place them on a different location, please regard this in all further instructions.


The previous example does not contain the <code>BIND9_DLZ</code> configuration required for setting up a Samba AD DNS server. For details how to set up the module, see [[BIND9_DLZ_DNS_Back_End|BIND9_DLZ DNS Back End]].
For more details on the parameters used in the sample 'named.conf', see 'man 5 named.conf'.


{{Imbox
| type = important
| text = You must not add the AD domain forward or reverse zone records to the named.conf files, these zones are stored dynamically in AD.
}}




== Adding a user and group for BIND ==


== Downloading the DNS Root Servers List ==
If you don't want to run bind as root (and I'm sure you don't want that!), we add an account and group.


* Download the latest list of the DNS root servers to the <code>/var/named/named.root</code> file:
First check if we have an existing `named` group:


# wget -q -O /var/named/named.root http://www.internic.net/zones/named.root
# getent group|grep named


Add the user and group if none exists (adapt the UID/GID if required) :
* Enable the BIND user to read the root servers list:


# groupadd -g 25 named
# chown root:named /var/named/named.root
# useradd -g named -u 25 -d /var/named -M -s /sbin/nologin named
# chmod 640 /var/named/named.root


{{Imbox
| type = note
| text = Optionally, set up a Cron job to automatically update the file.
}}




== Getting the root name server list ==


== Creating the localhost Zone File ==
Download the root name server list from InterNIC:


* Create the <code>localhost</code> forward zone in the <code>/var/named/master/localhost.zone</code> file:
# wget -q -O /var/named/named.root http://www.internic.net/zones/named.root
# chown named:named /var/named/named.root

To have always the current file, you can add a cronjob to automatically download.



== Creating the localhost zone file ==

Create a forward zone file ('/var/named/master/localhost.zone') for your 'localhost' zone:


$TTL 3D
$TTL 3D
Line 147: Line 208:
IN A 127.0.0.1
IN A 127.0.0.1


* Enable the BIND user to read the zone file:
# chown named:named /var/named/master/localhost.zone
# chmod 640 /var/named/master/localhost.zone




== Creating the 0.0.127.in-addr.arpa zone file ==


Create a reverse zone file ('/var/named/master/0.0.127.zone') for your '0.0.127.in-addr.arpa' zone:
== Creating the 0.0.127.in-addr.arpa Zone File ==

* Create the <code>0.0.127.in-addr.arpa</code> reverse zone in the <code>/var/named/master/0.0.127.zone</code> file:


$TTL 3D
$TTL 3D
Line 168: Line 233:




* Enable the BIND user to read the zone file:


# chown named:named /var/named/master/0.0.127.zone
== Set permissions on the zone files ==
# chmod 640 /var/named/master/0.0.127.zone


# chown named:named /var/named/master/*.zone
# chmod 640 /var/named/master/*.zone








= Installing & Configuring BIND on Debian based distros =


== Installing the required packages ==
= Starting BIND =

You need to install the following packages:

apt-get install -y bind9 bind9utils

{{Imbox
| type = note
| text = Before continuing, you will need to provision a DC in a new domain or join as a DC to an existing domain or upgrade from the existing internal DNS server to BIND9_DLZ. Various required files will only be created by doing one of the preceeding actions.
}}


== Setting up the named.conf files ==

On Debian based distros, you have 5 Bind9 files:

/etc/default/bind9
/etc/bind/named.conf
/etc/bind/named.conf.options
/etc/bind/named.conf.local
/etc/bind/named.conf.default-zones

Of these, only two or three need to be configured.

If you only use ipv4, edit : <code>/etc/default/bind9</code> and Change:

OPTIONS="-u bind"

To:

OPTIONS="-u bind -4"

The second file <code>/etc/bind/named.conf</code>, Shouldn't need modification, as it just contains links to the other <code>named.conf</code> files:

include "/etc/bind/named.conf.options";
include "/etc/bind/named.conf.local";
include "/etc/bind/named.conf.default-zones";

The third file <code>/etc/bind/named.conf.options</code>, is the one you need to configure for your Active Directory and to setup default ACL's for Bind9.

// Managing acls
acl internals { 127.0.0.0/8; 192.168.0.0/24; };
options {
directory "/var/cache/bind";
version "Go Away 0.0.7";
notify no;
empty-zones-enable no;
auth-nxdomain yes;
forwarders { 8.8.8.8; 8.8.4.4; };
allow-transfer { none; };
dnssec-validation no;
dnssec-enable no;
dnssec-lookaside no;
// If you only use IPv4.
listen-on-v6 { none; };
// listen on these ipnumbers.
listen-on port 53 { 192.168.0.6; 127.0.0.1; ::1; };
// Added Per Debian buster Bind9.
// Due to : resolver: info: resolver priming query complete messages in the logs.
// See: https://gitlab.isc.org/isc-projects/bind9/commit/4a827494618e776a78b413d863bc23badd14ea42
minimal-responses yes;
// Add any subnets or hosts you want to allow to use this DNS server
allow-query { "internals"; };
allow-query-cache { "internals"; };
// Add any subnets or hosts you want to allow to use recursive queries
recursion yes;
allow-recursion { "internals"; };
// https://wiki.samba.org/index.php/Dns-backend_bind
// DNS dynamic updates via Kerberos (optional, but recommended)
// ONE of the following lines should be enabled AFTER you provision or join a DC with bind9_dlz
// or AFTER upgrading your dns from internal to bind9_dlz
// Before Samba 4.9.0
// tkey-gssapi-keytab "/var/lib/samba/private/dns.keytab";
// From Samba 4.9.0 ( You will need to run samba_dnsupgrade if upgrading your Samba version. )
tkey-gssapi-keytab "/var/lib/samba/bind-dns/dns.keytab";
};

The fourth file <code>/etc/bind/named.conf.local</code>, just needs the addition of one line, to link in another file provided by Samba:

include "/var/lib/samba/bind-dns/named.conf";

The last file <code>/etc/bind/named.conf.default-zones</code> does not require any changes.

= Starting the Daemon =

To start the BIND daemon as the <code>named</code> user, run


# named -u named
# named -u named


Alternatively, use your operating system tools, such as <code>systemctl</code> or <code>service</code>, to start the daemon. See your distribution's documentation for details.
If the configuration is valid, you should see no errors on the console and in the system logfile.


{{Imbox
To have BIND automatically started at boot time, it's recommended to create a init.d script or start it by systemd.
| type = note
| text = Enable the daemon to start automatically when the system boots. For details, see your distribution's documentation.
}}


{{Imbox
| type = note
| text = You should ensure that you never <code>reload</code> Bind9, you should check your init files and change <code>reload</code> to <code>restart</code>, you should also check <code>/etc/logrotate.d/named</code> etc.
}}






= Testing Your Zones =


The following examples query the DNS service on the local machine (<code>127.0.0.1</code>):
= Testing your zone =


To test the <code>localhost</code> forward zone:
Now we will try to lookup our zone entries. We tell the 'host' command to use the resolver on 127.0.0.1, so that we don't query a foreign DNS server that is also configured in '/etc/resolv.conf'.


# host -t A localhost 127.0.0.1
First check the forward lookup for 'localhost':
# host localhost. 127.0.0.1
Using domain server:
Using domain server:
Name: 127.0.0.1
Name: 127.0.0.1
Address: 127.0.0.1#53
Address: 127.0.0.1#53
Aliases:
Aliases:
localhost has address 127.0.0.1
localhost has address 127.0.0.1


To test the <code>0.0.127.in-addr.arpa</code> reverse zone:
And then the reverse lookup for '127.0.0.1':

# host 127.0.0.1 127.0.0.1
# host -t PTR 127.0.0.1 127.0.0.1
Using domain server:
Using domain server:
Name: 127.0.0.1
Name: 127.0.0.1
Address: 127.0.0.1#53
Address: 127.0.0.1#53
Aliases:
Aliases:
1.0.0.127.in-addr.arpa domain name pointer localhost.
1.0.0.127.in-addr.arpa domain name pointer localhost.


Line 215: Line 380:




= Configuring BIND as Samba Active Directory backend =


See [[BIND9_DLZ_DNS_Back_End|Configuring BIND9_DLZ as Back End for Samba AD]].
= Configuring the BIND9_DLZ module =

For details, see See [[BIND9_DLZ_DNS_Back_End|BIND9_DLZ DNS Back End]].





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

Revision as of 14:44, 2 September 2019

Introduction

If you are planning to set up a Samba Active Directory (AD) domain controller (DC) using the BIND9_DLZ back end, you have to install and configure the BIND DNS server first.

The following describes how to set up a basic BIND installation you can use as Samba AD DC back end.



Installing BIND

For a list of supported BIND versions, see Configuring the BIND9_DLZ module.


Package Installation

Installing BIND using packages provided with your distribution is the recommended way. Select this installation mode for an easy installation and to automatically receive updates when available. For details how to install packages, see the distribution's package manager documentation.

Make sure that your package provider compiled BIND using the following options:

  • --with-gssapi=yes or --with-gssapi=/usr (or similar) for secure dynamic DNS updates using Kerberos
  • --with-dlopen dynamically loadable zones (DLZ)

To list the build options:

# named -V
BIND 9.x.y built with ... '--with-dlopen=yes' '--with-gssapi=yes' ...



Compiling and Installing BIND

Use this installation mode if you are an advanced user and know how to compile software.


Downloading the Sources

Download a supported BIND version from https://www.isc.org/software/bind.


Compiling BIND

  • Pass at least the following parameters to the configure command:
# ./configure --with-gssapi=/usr/include/gssapi --with-dlopen=yes
Add further parameters, if required.
  • To build and install, run:
# make
# make install


Adding a User and Group for BIND

For security reasons, do not run BIND as root user.

To create a named group using GID 25:

# groupadd -g 25 named

To create a named account with UID 25, primary group named, home directory /var/named/, and without a valid shell:

# useradd -u 25 -g named -d /var/named -M -s /sbin/nologin named

For details, see the useradd (8) and groupadd (8) man page.



Configuring BIND

Setting up a named.conf file

To locate the directory, BIND uses to read the named.conf file:

# named -V
BIND 9.x.y built with ... '--sysconfdir=/etc' ...

In the previous example, BIND reads the configuration from the /etc/named.conf file.

The following is a basic configuration file:

# Global Configuration Options
options {

    auth-nxdomain yes;
    directory "/var/named";
    notify no;
    empty-zones-enable no;

    # IP addresses and network ranges allowed to query the DNS server:
    allow-query {
        127.0.0.1;
        10.99.1.0/24;
    };

    # IP addresses and network ranges allowed to run recursive queries:
    # (Zones not served by this DNS server)
    allow-recursion {
        127.0.0.1;
        10.1.1.0/24;
    };

    # Forward queries that can not be answered from own zones
    # to these DNS servers:
    forwarders {
        8.8.8.8;
        8.8.4.4;
    };

    # Disable zone transfers 
    allow-transfer {
        none;
    };
 };

# Root Servers
# (Required for recursive DNS queries)
zone "." {
   type hint;
   file "named.root";
};

# localhost zone
zone "localhost" {
    type master;
    file "master/localhost.zone";
};

# 127.0.0. zone.
zone "0.0.127.in-addr.arpa" {
    type master;
    file "master/0.0.127.zone";
};

For details about the used parameters and options, see the named.conf (5) man page.

The previous example does not contain the BIND9_DLZ configuration required for setting up a Samba AD DNS server. For details how to set up the module, see BIND9_DLZ DNS Back End.


Downloading the DNS Root Servers List

  • Download the latest list of the DNS root servers to the /var/named/named.root file:
# wget -q -O /var/named/named.root http://www.internic.net/zones/named.root
  • Enable the BIND user to read the root servers list:
# chown root:named /var/named/named.root
# chmod 640 /var/named/named.root


Creating the localhost Zone File

  • Create the localhost forward zone in the /var/named/master/localhost.zone file:
$TTL 3D

$ORIGIN localhost.

@       1D      IN     SOA     @       root (
                       2013050101      ; serial
                       8H              ; refresh
                       2H              ; retry
                       4W              ; expiry
                       1D              ; minimum
                       )

@       IN      NS      @
        IN      A       127.0.0.1
  • Enable the BIND user to read the zone file:
# chown named:named /var/named/master/localhost.zone
# chmod 640 /var/named/master/localhost.zone


Creating the 0.0.127.in-addr.arpa Zone File

  • Create the 0.0.127.in-addr.arpa reverse zone in the /var/named/master/0.0.127.zone file:
$TTL 3D

@       IN      SOA     localhost. root.localhost. (
                        2013050101      ; Serial
                        8H              ; Refresh
                        2H              ; Retry
                        4W              ; Expire
                        1D              ; Minimum TTL
                        )

       IN      NS      localhost.

1      IN      PTR     localhost.


  • Enable the BIND user to read the zone file:
# chown named:named /var/named/master/0.0.127.zone
# chmod 640 /var/named/master/0.0.127.zone



Installing & Configuring BIND on Debian based distros

Installing the required packages

You need to install the following packages:

apt-get install -y bind9 bind9utils


Setting up the named.conf files

On Debian based distros, you have 5 Bind9 files:

/etc/default/bind9 
/etc/bind/named.conf
/etc/bind/named.conf.options
/etc/bind/named.conf.local
/etc/bind/named.conf.default-zones

Of these, only two or three need to be configured.

If you only use ipv4, edit : /etc/default/bind9 and Change:

OPTIONS="-u bind"

To:

OPTIONS="-u bind -4"

The second file /etc/bind/named.conf, Shouldn't need modification, as it just contains links to the other named.conf files:

include "/etc/bind/named.conf.options";
include "/etc/bind/named.conf.local";
include "/etc/bind/named.conf.default-zones";

The third file /etc/bind/named.conf.options, is the one you need to configure for your Active Directory and to setup default ACL's for Bind9.

// Managing acls
acl internals { 127.0.0.0/8; 192.168.0.0/24; };

options {
      directory "/var/cache/bind";
      version "Go Away 0.0.7";
      notify no;
      empty-zones-enable no;
      auth-nxdomain yes;
      forwarders { 8.8.8.8; 8.8.4.4; };
      allow-transfer { none; };

      dnssec-validation no;
      dnssec-enable no;
      dnssec-lookaside no;

      // If you only use IPv4. 
      listen-on-v6 { none; };
      // listen on these ipnumbers. 
      listen-on port 53 { 192.168.0.6; 127.0.0.1; ::1; };

      // Added Per Debian buster Bind9. 
      // Due to : resolver: info: resolver priming query complete messages in the logs. 
      // See: https://gitlab.isc.org/isc-projects/bind9/commit/4a827494618e776a78b413d863bc23badd14ea42
      minimal-responses yes;

      //  Add any subnets or hosts you want to allow to use this DNS server
      allow-query { "internals";  };
      allow-query-cache { "internals"; };

      //  Add any subnets or hosts you want to allow to use recursive queries
      recursion yes;
      allow-recursion {  "internals"; };

      // https://wiki.samba.org/index.php/Dns-backend_bind
      // DNS dynamic updates via Kerberos (optional, but recommended)
      // ONE of the following lines should be enabled AFTER you provision or join a DC with bind9_dlz 
      // or AFTER upgrading your dns from internal to bind9_dlz 
      // Before Samba 4.9.0
      // tkey-gssapi-keytab "/var/lib/samba/private/dns.keytab";
      // From Samba 4.9.0 ( You will need to run samba_dnsupgrade if upgrading your Samba version. ) 
      tkey-gssapi-keytab "/var/lib/samba/bind-dns/dns.keytab";

  };

The fourth file /etc/bind/named.conf.local, just needs the addition of one line, to link in another file provided by Samba:

include "/var/lib/samba/bind-dns/named.conf";

The last file /etc/bind/named.conf.default-zones does not require any changes.

Starting the Daemon

To start the BIND daemon as the named user, run

# named -u named

Alternatively, use your operating system tools, such as systemctl or service, to start the daemon. See your distribution's documentation for details.


Testing Your Zones

The following examples query the DNS service on the local machine (127.0.0.1):

To test the localhost forward zone:

# host -t A localhost 127.0.0.1
Using domain server:
Name: 127.0.0.1
Address: 127.0.0.1#53
Aliases: 
localhost has address 127.0.0.1

To test the 0.0.127.in-addr.arpa reverse zone:

# host -t PTR 127.0.0.1 127.0.0.1
Using domain server:
Name: 127.0.0.1
Address: 127.0.0.1#53
Aliases: 
1.0.0.127.in-addr.arpa domain name pointer localhost.



Configuring the BIND9_DLZ module

For details, see See BIND9_DLZ DNS Back End.