Force user samba4 howto

Setting up Samba as an Active Directory Domain Controller

Starting from version 4.0, Samba is able to run as an Active Directory (AD) domain controller (DC). If you are installing Samba in a production environment, it is recommended to run two or more DCs for failover reasons.

This documentation describes how to set up Samba as the first DC to build a new AD forest. Additionally, use this documentation if you are migrating a Samba NT4 domain to Samba AD. To join Samba as an additional DC to an existing AD forest, see Joining a Samba DC to an Existing Active Directory.

Samba as an AD DC only supports:

Samba provides experimental support for the MIT Kerberos KDC provided by your operating system if you run Samba 4.7 or later and has been built using the option. In other cases Samba uses the Heimdal KDC included in Samba. For further details about Samba using the MIT KDC, and why it is experimental see Running a Samba AD DC with MIT Kerberos KDC.
  • Select a host name for your AD DC.
Do not use NT4-only terms as host name, such as or. These modes do not exist in an AD and cause confusion.
  • Select a DNS domain for your AD forest. The name will also be used as the AD Kerberos realm.
Make sure that you provision the AD using a DNS domain that will not need to be changed. Samba does not support renaming the AD DNS zone and Kerberos realm. Do not use for the TLD, this is used by Avahi.
For additional information, see Active Directory Naming FAQ.
  • Use a static IP address on the DC.
  • Disable tools, such as, that automatically update your DNS resolver configuration file. AD DCs and domain members must use an DNS server that is able to resolve the AD DNS zones.
  • Verify that no Samba processes are running:
# ps ax | egrep "samba | smbd | nmbd | winbindd"
If the output lists any,,, or processes, shut down the processes.
  • Verify that the file on the DC correctly resolves the fully-qualified domain name (FQDN) and short host name to the LAN IP address of the DC. For example: localhost DC1
The host name and FQDN must not resolve to the IP address or any other IP address than the one used on the LAN interface of the DC.
  • If you previously ran a Samba installation on this host:
  • Remove the existing file. To list the path to the file:
# smbd -b | grep "CONFIGFILE" CONFIGFILE: /usr/local/samba/etc/samba/smb.conf
  • Remove all Samba database files, such as and files. To list the folders containing Samba databases:
# smbd -b | egrep "LOCKDIR | STATEDIR | CACHEDIR | PRIVATE_DIR" LOCKDIR: / usr / local / samba / var / lock / STATEDIR: / usr / local / samba / var / locks / CACHEDIR: / usr / local / samba / var / cache / PRIVATE_DIR : / usr / local / samba / private /
Starting with a clean environment helps to prevent confusion and ensures that no files from any previous Samba installation will be mixed with your new domain DC installation.
  • Remove an existing file:
# rm /etc/krb5.conf

The Samba AD provisioning process creates the AD databases and adds initial records, such as the domain administrator account and required DNS entries.

If you are migrating a Samba NT4 domain to AD, skip this step and run the Samba classic upgrade. For details, see Migrating a Samba NT4 Domain to Samba AD (Classic Upgrade).

The AD provisioning requires root permissions to create files and set permissions.

The command provides several parameters to use with the interactive and non-interactive setup. For details, see:

# samba-tool domain provision --help
When provisioning a new AD, it is recommended to enable the NIS extensions by passing the parameter to the command. There are no disadvantages to enabling the NIS extensions, but enabling them in an existing domain requires manually extending the AD schema. For further details about Unix attributes in AD, see:

Parameter explanation

Set the following parameters during the provisioning:

Interactive mode setting Non-interactive mode parameters Explanation
Enables the NIS extensions required for the ADUC Unix Attributes tab.
Kerberos realm. The uppercase version of the AD DNS domain. For example: .
NetBIOS domain name (workgroup). This can be anything, but it must be one word, not longer than 15 characters and not containing a dot. It is recommended to use the first part of the AD DNS domain. For example: . Do not use the computers short hostname.
Installs the domain controller role.
Sets the DNS back end. The first DC in an AD must be installed using a DNS back end. Note that the is not supported and will be removed in a future Samba version.
not available This setting is only available when using the DNS back end. For details, see Setting up a DNS Forwarder.
Sets the domain administrator password. If the password does not match the complexity requirements, the provisioning fails. For details, see Microsoft TechNet: Passwords must meet complexity requirements.

Other parameters frequently used with the command:

  • : If your server has multiple network interfaces, use these options to bind Samba to the specified interfaces. This enables the command to register the correct LAN IP address in the directory during the join.
do NOT use as the DNS backend, it is not supported and will be removed in a future Samba version.
If using Bind as the DNS backend, do NOT use, it is not supported and will be removed in a future Samba version.
Once you have provisioned the first DC in an AD domain, do not provision any further DCs in the same domain, join any further DCs.

Provisioning Samba AD in Interactive Mode

To provision a Samba AD interactively, run:

# samba-tool domain provision --use-rfc2307 --interactive realm [SAMDOM.EXAMPLE.COM]: SAMDOM.EXAMPLE.COM Domain [SAMDOM]: SAMDOM server role (dc, member, standalone) [dc]: dc DNS backend (SAMBA_INTERNAL, BIND9_FLATFILE, BIND9_DLZ, NONE) [SAMBA_INTERNAL]: SAMBA_INTERNAL DNS forwarder IP address (write 'none' to disable forwarding) []: Administrator password: Passw0rd Retype password: Passw0rd Looking up IPv4 addresses Looking up IPv6 addresses No IPv6 address will be assigned Setting up share.ldb Setting up secrets.ldb Setting up the registry Setting up the privileges database Setting up idmap db Setting up SAM db Setting up sam.ldb partitions and settings Setting up sam.ldb rootDSE Pre -loading the Samba 4 and AD schema Adding DomainDN: DC = samdom, DC = example, DC = com Adding configuration container Setting up sam.ldb schema Setting up sam.ldb configuration data Setting up display specifiers Modifying display specifiers Adding users container Modifying users container Adding computers container Modifying computers container Setting up sam.ldb data Setting up well known security principals Setting up sam.ldb rootDSE marking as synchronized Fixing provision GUIDs A Kerberos configuration suitable for Samba 4 has been generated at /usr/local/samba/private/ DOMAIN SID: S-1-5-21 -2614513918-2685075268-614796884
The interactive provisioning mode supports passing further parameters to the command. This enables you to modify parameters that are not part of the interactive setup.

Provisioning Samba AD in non-interactive mode

For example, to provision a Samba AD non-interactively with the following settings:

  • Server role:
  • NIS extensions enabled
  • Internal DNS back end
  • Kerberos realm and AD DNS zone:
  • NetBIOS domain name:
  • Domain administrator password:
# samba-tool domain provision --server-role = dc --use-rfc2307 --dns-backend = SAMBA_INTERNAL --realm = SAMDOM.EXAMPLE.COM --domain = SAMDOM --adminpass = Passw0rd

Skip this step if you provisioned the DC using the DNS back end.

  • Start the BIND DNS server. For example:
# systemctl start named
For details on how to start services, see you distribution's documentation.

Domain members in an AD use DNS to locate services, such as LDAP and Kerberos. For that, they need to use a DNS server that is able to resolve the AD DNS zone.

On your DC, set the AD DNS domain in the and the IP of your DC in the parameter of the file. For example:

search nameserver

You can optionally add a reverse lookup zone.

# samba-tool dns zonecreate Password for [[email protected]]: Zone .arpa created successfully

If you need more than one reverse zone (multiple subnets), just run the above command again but with the data for the other subnet.

The reverse zone is directly live without restarting Samba or BIND.

In an AD, Kerberos is used to authenticate users, machines, and services.

During the provisioning, Samba created a Kerberos configuration file for your DC. Copy this file to your operating system's Kerberos configuration. For example:

# cp /usr/local/samba/private/krb5.conf /etc/krb5.conf
Do not create a symbolic link to the generated file. In Samba 4.7 and later, the directory is no longer accessible by other users than the user. If the file is a symbolic link, other users are not able to read the file and, for example, dynamic DNS updates fail if you use the DNS back end.

The pre-created Kerberos configuration uses DNS service (SRV) resource records to locate the KDC.

To start the service manually, enter:

# samba

Samba does not provide System V init scripts,,, or other services configuration files.

  • If you installed Samba using packages, use the script or service configuration file included in the package to start Samba.
  • If you built Samba, see Managing the Samba AD DC Service.

Verifying the file server

To list all shares provided by the DC:

Before Samba 4.11.0:

$ smbclient -L localhost -N Anonymous login successful Domain = [SAMDOM] OS = [Unix] Server = [Samba xyz] Sharename Type Comment --------- ---- ------- netlogon Disk sysvol Disk IPC $ IPC IPC Service (Samba xyz) Domain = [SAMDOM] OS = [Unix] Server = [Samba xyz] Server Comment --------- ------- Workgroup Master - ------- -------

From Samba 4.11.0:

smbclient -L localhost -N Anonymous login successful Sharename Type Comment --------- ---- ------- sysvol Disk netlogon Disk IPC $ IPC IPC Service (Samba 4.12.6-Debian) SMB1 disabled - no workgroup available
The and shares were auto-created during the provisioning and must exist on a DC.

To verify authentication, connect to the share using the domain administrator account:

$ smbclient // localhost / netlogon -UAdministrator -c 'ls' Enter Administrator's password: Domain = [SAMDOM] OS = [Unix] Server = [Samba x.y.z]. D 0 Tue Nov 1 08:40:00 2016 .. D 0 Tue Nov 1 08:40:00 2016 49386 blocks of size 524288. 42093 blocks available

If one or more tests fail, see Troubleshooting.

Verifying DNS

To verify that your AD DNS configuration works correctly, query some DNS records:

  • The tcp-based SRV record in the domain:
$ host -t SRV has SRV record 0 100 389
  • The udp-based SRV resource record in the domain:
$ host -t SRV has SRV record 0 100 88
  • The A record of the domain controller:
$ host -t A has address

If one or more tests fail, see Troubleshooting.

Verifying Kerberos

  • Request a Kerberos ticket for the domain administrator account:
$ kinit administrator Password for [email protected]:
If you do not pass the principal in the format to the command, the Kerberos realm is automatically appended.
Always enter the Kerberos realm in uppercase.
  • List the cached Kerberos tickets:
$ klist Ticket cache: FILE: / tmp / krb5cc_0 Default principal: [email protected] Valid starting Expires Service principal 01.11.2016 08:45:00 12.11.2016 18:45:00 krbtgt / SAMDOM.EXAMPLE.COM @ SAMDOM.EXAMPLE.COM renew until 02.11.2016 08:44:59

If one or more tests fail, see Troubleshooting.

Kerberos requires synchronized time on all domain members. For further details and how to set up the or service, see Time Synchronization.

Whilst the Samba AD DC is able to provide file shares, just like all other installation modes, the Samba team does not recommend using a DC as a file server for the following reasons:

  • For anything but the smallest organizations, having more than one DC is a really good backup measure, and makes upgrades safer
  • It encourages upgrades of the DC to also be upgrades of the host OS every year or two, because there isn't complex data to transition or other services involved.
  • This means upgrades can be done by installing fresh, and replicating in the changes, which is better tested in Samba, gains new features and avoids a number of lingering data corruption risks.
  • The DC and file server have different points at which an organization would wish to upgrade. The needs for new features on the DC and file server come at different times. Currently the AD DC is evolving rapidly to gain features, whereas the fileserver, after over 20 years, is quite rightly more conservative.
  • mandatory smb signing is enforced on the DC.

If you do decide to use the Samba DC as a fileserver, please consider running a VM, on the DC, containing a separate Samba Unix domain member and use this instead.

If you must use the Samba DC as a fileserver, you should be aware that the auto-enabled virtual file system (VFS) object enables you to only configure shares with Windows access control lists (ACL). Using POSIX ACLs with shares on a Samba DC does not work.

You should be aware that if wish to use a vfs object on a DC share e.g. recycle, you must not just set in the share. Doing this will turn off the default vfs objects and. You must set.

To provide network shares with the full capabilities of Samba, set up a Samba domain member with file shares. For details, see:

If you only have a small domain (small office, home network) and do not want to follow the Samba team's recommendation and use the DC additionally as a file server, configure Winbindd before you start setting up shares. For details, see Configuring Winbindd on a Samba AD DC.

If you do use an AD DC as a fileserver, you must be aware that it can be problematic and can cause strange errors.
If you do use an AD DC as a fileserver, do not add any of the 'idmap config' lines used on a Unix domain member. They will not work and will cause problems.
If you do use an AD DC as a fileserver, you must set the permissions from Windows, do not attempt to use any of the old methods (force user etc). They will not work correctly and will cause problems.

For further details, see Samba AD DC Troubleshooting.

See User Documentation.