Setting up Samba as a Standalone Server

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Introduction

In small networks, such as a home network, or to share folders on a host that is not part of a domain, you often do not want to set up an Active Directory or NT4 domain.

The following documentation describes how to set up a Samba standalone server providing:

  • a share that is accessible anonymously (guest access).
  • a share that requires authentication against a local user database on the Samba host.



Creating a Basic guest only smb.conf File

The following is a minimal configuration for a Samba standalone server that only allows guest access: 

[global]
        map to guest = Bad User
        log file = /var/log/samba/%m
        log level = 1
        server role = standalone server

[guest]
        # This share allows anonymous (guest) access
        # without authentication!
        path = /srv/samba/guest/
        read only = no
        guest ok = yes
        guest only = yes




Creating a Basic authenticated access smb.conf File

The following is a minimal configuration for a Samba standalone server: 

[global]
        log file = /var/log/samba/%m
        log level = 1
        server role = standalone server

[demo]
        # This share requires authentication to access
        path = /srv/samba/demo/
        read only = no
        inherit permissions = yes
  • You can set a workgroup name with workgroup = xxxxxxxx, where 'xxxxxxxx' is the required name. If the parameter isn't set, the default workgroup name 'WORKGROUP' will be used.
  • You can restrict access to members of a specified group by adding valid users = @demoGroup to the share, you will need to replace demoGroup with the required Unix group name.
  • The log parameters are not necessary for a minimal setup. However they are useful to set the log file and increasing the log level in case of problems.
  • Whilst these are only minimal smb.conf files, you can add other parameters, such as 'unix password sync = yes' to ensure the Unix & Samba passwords are kept in sync. See 'man smb.conf' for more info.




Creating a Local User Account

To provide authentication on a standalone host, you have to create the accounts locally on the operating system and additionally in the Samba database. By default, Samba uses the tdbsam back end and stores the database in the /usr/local/samba/private/passdb.tdb file. Optionally set a different location in the smb.conf file using the passdb backend parameter. See the smb.conf 5 man page for details.

  • Create a demoUser account on the local system:
# useradd -M -s /sbin/nologin demoUser
Omit the -M parameter if the user requires a home directory on this host. For Samba access, the account does not require a valid shell.
  • To enable the demoUser account on the local system:
# passwd demoUser
Enter new UNIX password: Passw0rd
Retype new UNIX password: Passw0rd
passwd: password updated successfully
Setting a local password is required to enable the account. Samba denies access if the account is disabled locally. Local log ins using this password are not possible if the account was created without a valid shell.
  • Add the demoUser account to the Samba database:
# smbpasswd -a demoUser
New SMB password: Passw0rd
Retype new SMB password: Passw0rd
Added user demoUser.
The password assigned in these steps is the one used by the user to log in to the domain.



Local Group Management

  • To create a demoGroup group:
# groupadd demoGroup
  • To add the demoUser account to the group:
# usermod -aG demoGroup demoUser



Creating the Shared Directories

To create the shares directories: 

# mkdir -p /srv/samba/guest/
# mkdir -p /srv/samba/demo/



Setting ACLs on the Shared Directories

Set the following POSIX permissions: 

# chown -R nobody:nogroup /srv/samba/guest/
# chgrp -R demoGroup /srv/samba/demo/

# chmod 2770 /srv/samba/guest/
# chmod 2770 /srv/samba/demo/

This configures write access to members of the demoGroup group in both directories. Other users have read access in the /srv/samba/guest/ and no access in the /srv/samba/demo/ directory. The SGID bit - represented by the first bit (2) in the mode set on the directories - inherits the group of the parent directory instead setting it to the users primary group when new files are created.

For further information, see Setting up a Share Using POSIX ACLs.



Verifying the Samba configuration

You should verify the Samba configuration every time the /etc/samba/smb.conf file is updated by using the testparm utility

You can simply execute it as follows: 

# testparm -s

Sample output: 

Load smb config files from /etc/samba/smb.conf
Loaded services file OK.
Server role: ROLE_STANDALONE

Press enter to see a dump of your service definitions
...

If any errors are shown (you can ignore deprecation warnings), fix them before proceeding.



Starting Samba

Start the smbd daemon: 

# smbd

Samba does not include start scripts. See your distribution's documentation how further information how to automatically start a service at boot time.



Testing the Share Access

  • Access the demo share as user demoUser:
# smbclient -U demoUser //SA/demo
Enter demoUser's password: Passw0rd
Domain=[WORKGROUP] OS=[Windows 6.1] Server=[Samba x.y.z]
smb: \> ls
  .                                   D        0  Sun Jan  3 21:00:00 2016
  ..                                  D        0  Sun Jan  3 19:00:00 2016
  demo.txt                            A        0  Sun Jan  3 21:00:00 2016

		9943040 blocks of size 1024. 7987416 blocks available
smb: \> quit
  • Access the demo share as guest. The access is denied:
# smbclient -U guest //SA/demo
Enter guest's password: 
Domain=[WORKGROUP] OS=[Windows 6.1] Server=[Samba x.y.z]
tree connect failed: NT_STATUS_ACCESS_DENIED


.


Advanced share settings

This section describes some advanced share configuration parameters. For further information about the used parameters, see the smb.conf (5) man page.


Using the force Parameters

[demo]
        path = /srv/samba/demo/
        read only = no
        force create mode = 0660
        force directory mode = 2770
        force user = demoUser
        force group = demoGroup

The force create mode and force directory mode parameters force Samba to create new files and folders with the set permissions.

The force user and force group parameters map all connections to the specified user and group. Note that this can cause security problems if all users connecting to a share are mapped to a specific user account or group in the background.


User and Group-based Share Access

See Configuring User and Group-based Share Access.


Host-based Share Access

See Configuring Host-based Share Access.



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