Setting up Samba as a Domain Member

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Revision as of 11:06, 26 October 2021 by Hortimech (talk | contribs)


A Samba domain member is a Linux machine joined to a domain that is running Samba and does not provide domain services, such as an NT4 primary domain controller (PDC) or Active Directory (AD) domain controller (DC).

On a Samba domain member, you can:

  • Use domain users and groups in local ACLs on files and directories.
  • Set up shares to act as a file server.
  • Set up printing services to act as a print server.
  • Configure PAM to enable domain users to log on locally or to authenticate to local installed services.

For details about setting up a Samba NT4 domain or Samba AD, see Domain Control.

Preparing the Installation

General Preparation

  • Verify that no Samba processes are running:
# ps ax | egrep "samba|smbd|nmbd|winbindd"
If the output lists any samba, smbd, nmbd, or winbindd processes, shut down the processes.
  • If you previously run a Samba installation on this host:
  • Backup the existing smb.conf file. To list the path to the file, enter:
# smbd -b | grep "CONFIGFILE"
   CONFIGFILE: /usr/local/samba/etc/samba/smb.conf
  • Remove all Samba database files, such as *.tdb and *.ldb files. To list the folders containing Samba databases:
  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 you to prevent confusion, and no files from your previous Samba installation are mixed with your new domain member installation.

Preparing a Domain Member to Join an Active Directory Domain

Configuring DNS

Active Directory (AD) uses DNS in the background, to locate other DCs and services, such as Kerberos. Thus AD domain members and servers must be able to resolve the AD DNS zones.

The following describes how to manually configure Linux clients to use DNS servers. If you are running a DHCP server providing DNS settings to your client computers, configure your DHCP server to send the IP addresses of your DNS servers.

Configuring the /etc/resolv.conf

Set the DNS server IP and AD DNS domain in your /etc/resolv.conf. For example:


Some utilities, such as NetworkManager can overwrite manual changes in that file. See your distribution's documentation for information about how to configure name resolution permanently.

For NetworkManager, set the DNS server using either the graphical interface or nmcli and restart the NetworkManager service. The visible /etc/resolv.conf file:


won't list the DNS server explicitly but nevertheless works correctly.

Testing DNS resolution

To verify that your DNS settings are correct and your client or server is able to resolve IP addresses and host names use the nslookup or host commands. The nslookup command is available on Linux and Windows.

Forward Lookup

To resolve a host name its IP address:

# nslookup


alternatively you can use the host command:

# host has address

Reverse Lookup

To resolve a IP address to its host name:

# nslookup
Address:	name =


# host domain name pointer

Note that in a Samba AD, the reverse zone is not automatically configured. To set up a reverse zone, see DNS Administration.

Resolving SRV Records

Active Directory (AD) uses SRV records to locate services, such as Kerberos and LDAP. To verify that SRV records are resolved correctly, use the nslookup interactive shell:

$ nslookup
> set type=SRV
Address:	service = 0 100 389	service = 0 100 389
> exit


$ host -t SRV has SRV record 0 100 389 has SRV record 0 100 389

Error Messages

  • The DNS server is not able to resolve the host name:
** server can't find NXDOMAIN
  • The DNS server is not able to resolve the IP address:
** server can't find NXDOMAIN
  • The DNS server used is not available:
;; connection timed out; no servers could be reached

Configuring Kerberos

Samba supports Heimdal and MIT Kerberos back ends. To configure Kerberos on the domain member, set the following in your /etc/krb5.conf file:

	default_realm = SAMDOM.EXAMPLE.COM
	dns_lookup_realm = false
	dns_lookup_kdc = true

The previous example configures Kerberos for the SAMDOM.EXAMPLE.COM realm.

The Samba teams recommends to no set any further parameters in the /etc/krb5.conf file.

If your /etc/krb5.conf contains an include line it will not work, you Must remove this line.

Configuring Time Synchronisation

Kerberos requires a synchronised time on all domain members. Thus it is recommended to set up an NTP client. For further details, see Configuring Time Synchronisation on a Unix Domain Member.

Local Host Name Resolution

When you join the host to the domain, Samba tries to register the host name in the AD DNS zone. For this, the net utility must be able to resolve the host name using DNS or using a correct entry in the /etc/hosts file.

To verify that your host name resolves correctly, use the getent hosts command. For example:

# getent hosts M1    M1

The host name and FQDN must not resolve to the IP address or any other IP address other than the one used on the LAN interface of the domain member.

If no output is displayed or the host is resolved to the wrong IP address and you are not using dhcp, set the correct entry in the /etc/hosts file. For example:      localhost    M1

If you are using dhcp, check that /etc/hosts only contains the '' line shown above. If you continue to have problems, contact the sysadmin who controls your DHCP server.

  • On debian related systems you will also see the line hostname in /etc/hosts, remove it before you install samba.
  • Please keep the line : localhost

if you need to add aliases to the machine hostname, add them to the end of the line that starts with the machines ipaddress, not the line.

Preparing a Domain Member to Join an NT4 Domain

For joining a host to an NT4 domain, no preparation is required.

Installing Samba

For details, see Installing Samba.

Configuring Samba

Setting up a Basic smb.conf File

When Setting up smb.conf on a Unix domain member, you will need to make a few decisions.

  • Do you require users and groups to have the same IDs everywhere, including Samba AD DCs ?
  • Do you only want your users and groups to have the same IDs on Unix domain members ?

After making your decision, you will have another decision to make, this decision could affect what you think you have already decided.

  • Do you want or need individual users to have different login shells and/or Unix home directory paths ?

If you need your users to have different login shells and/or Unix home directory paths, or you want them to have the same ID everywhere, you will need to use the winbind 'ad' backend and add RFC2307 attributes to AD.

It is recommended that your users will only use the Samba AD DC for authentication and will not store data on it or log into it. It is further recommended that you set up Unix domain members, using one of the the winbind backends, and use these as fileservers, printservers, etc. If you use the 'rid' or 'autorid' winbind backend, these will calculate the user and group IDs from the Windows RID, if you use the same [global] section of the smb.conf on every Unix domain member, you will get the same IDs. If you use the 'rid' or 'autorid' backend you do not need to add anything to AD and in fact, any RFC2307 attributes will be ignored. When using these backends you must set the 'template shell' and 'template homedir' parameters in smb.conf, these are global settings and everyone gets the same login shell and Unix home directory path, unlike the RFC2307 attributes where you can set individual Unix home directory paths and shells.

If you require your users and groups to have the same ID everywhere and have different login shell's and Unix home directory path's, you can do this by using the winbind 'ad' backend. If you only require the same ID everywhere with the same login shell and Unix home directory, you will need to add the template lines to smb.conf. If you do use the 'ad' backend, you need to add the relevant RFC2307 attributes to AD.

Having decided which winbind backend to use, you now have a further decision to make, the ranges to use with 'idmap config' in smb.conf. By default on a Unix domain member, there are multiple blocks of users & groups:

  • The local system users & groups: These will be from 0-999
  • The local Unix users and groups: These start at 1000
  • The 'well Known SIDs':  ????
  • The DOMAIN users and groups: ADUC, by default, starts these at 10000
  • Trusted domains:  ????
  • Anything that isn't a 'well Known SID' or a member of DOMAIN or a trusted domain: ????

As you can see from the above, you shouldn't set either the '*' or 'DOMAIN' ranges to start at 999 or less, as they would interfere with the local system users & groups. You also should leave a space for any local Unix users & groups, so starting the 'idmap config' ranges at 3000 seems to be a good compromise.

You need to decide how large your 'DOMAIN' is likely to grow to and you also need to know if you have any trusted domains or if you may need to have any in future.

Bearing the above information in mind, you could set the 'idmap config' ranges to the following:

Domain Range
* 3000-7999
DOMAIN 10000-999999

You could also have any trusted domains starting at:

Domain Range
TRUSTED 1000000-9999999

If you set the '*' range above the 'DOMAIN' range, the ranges will conflict if the 'Domain' grows to the point that the next ID would be the same as the '*' range start ID.

With the above suggested ranges, no range will overlap or interfere with another.

You may also have seen examples of the '*' range being used for everything, this is not recommended and should not be used.

Before joining the domain, configure the domain member's smb.conf file:

  • To locate the file, enter:
# smbd  -b | grep CONFIGFILE
  CONFIGFILE: /usr/local/samba/etc/smb.conf

To create a basic smb.conf, you need something like this (note, this does not include any 'idmap config' auth lines, they will be added later. It also does not show any shares)

   workgroup = SAMDOM
   security = ADS

   winbind refresh tickets = Yes
   vfs objects = acl_xattr
   map acl inherit = Yes
   store dos attributes = Yes

If you are creating a new smb.conf on an unjoined machine and add these lines, a keytab will be created during the join:

   dedicated keytab file = /etc/krb5.keytab
   kerberos method = secrets and keytab

If you do not want to enter the domain set in 'workgroup =' during login etc (just 'username' instead of DOMAIN\username) and have only one domain, add this line:

   winbind use default domain = yes

For testing purposes only (remove for production), add these lines:

   winbind enum users = yes
   winbind enum groups = yes

To disable printing completely, add these lines:

   load printers = no
   printing = bsd
   printcap name = /dev/null
   disable spoolss = yes

You now need to add the 'idmap config' lines for your preferred winbind method.

Choose backend for id mapping in winbindd

Select one of the following hyperlinks to find information about the relevant Samba domain back end and what idmap config lines to add:

Back End Documentation Man Page
ad idmap config ad idmap_ad(8)
rid idmap config rid idmap_rid(8)
autorid idmap config autorid idmap_autorid(8)

Mapping the Domain Administrator Account to the Local root User

Samba enables you to map domain accounts to a local account. Use this feature to execute file operations on the domain member's file system as a different user than the account that requested the operation on the client.

To map the domain administrator to the local root account:

  • Add the following parameter to the [global] section of your smb.conf file:
username map = /usr/local/samba/etc/
  • Create the /usr/local/samba/etc/ file with the following content:
!root = SAMDOM\Administrator

For further details, see username map parameter in the smb.conf(5) man page.

Joining the Domain

  • To join the host to an Active Directory (AD), enter:
# net ads join -U administrator
Enter administrator's password: Passw0rd
Using short domain name -- SAMDOM
Joined 'M1' to dns domain ''
  • To join the host to an NT4 domain, enter:
# net rpc join -U administrator
Enter administrator's password: Passw0rd
Joined domain SAMDOM.

Joining the Domain with samba-tool (>4.15.0 only)

  • To join the host to an Active Directory (AD), enter:
# samba-tool domain join MEMBER -U administrator

If you have problems joining the domain, check your configuration. For further help, see Troubleshooting Samba Domain Members.

Configuring the Name Service Switch

To enable the name service switch (NSS) library to make domain users and groups available to the local system:

  • Append the winbind entry to the following databases in the /etc/nsswitch.conf file:
passwd: files winbind
group:  files winbind
  • Keep the files entry as first source for both databases. This enables NSS to look up domain users and groups from the /etc/passwd and /etc/group files before querying the Winbind service.
  • Do not add the winbind entry to the NSS shadow database. This can cause the wbinfo utility fail.

Starting the Services

Start the following services to have a fully functioning Unix domain member:

  • The smbd service
  • The nmbd service
  • The winbindd service

Samba does not provide System V init scripts, systemd, upstart, or service files for other init services.

  • If you installed Samba using packages, use the script or service configuration file provided by the package to start Samba.
  • If you built Samba, see your distribution's documentation for how to create a script or configuration to start services.

Testing the Winbindd Connectivity

Sending a Winbindd Ping

To verify if the Winbindd service is able to connect to Active Directory (AD) Domain Controllers (DC) or a primary domain controller (PDC), enter:

# wbinfo --ping-dc
checking the NETLOGON for domain[SAMDOM] dc connection to "DC.SAMDOM.EXAMPLE.COM" succeeded

If the previous command fails, verify:

  • That the winbindd service is running.
  • Your smb.conf file is set up correctly.

Using Domain Accounts and Groups in Operating System Commands

Looking up Domain Users and Groups

The libnss_winbind library enables you to look up domain users and groups. For example:

  • To look up the domain user SAMDOM\demo01:
# getent passwd SAMDOM\\demo01
  • To look up the domain group Domain Users:
# getent group "SAMDOM\\Domain Users"
SAMDOM\domain users:x:10000:

Assigning File Permissions to Domain Users and Groups

The name service switch (NSS) library enables you to use domain user accounts and groups in commands. For example to set the owner of a file to the demo01 domain user and the group to the Domain Users domain group, enter:

# chown "SAMDOM\\demo01:SAMDOM\\domain users" file.txt

Setting up Additional Services on the Domain Member

On a Samba domain member, you can additionally set up:


For details, see Troubleshooting Samba Domain Members.