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Chapter 21. File and Print Servers

21.1. Samba

Samba is the standard open source Windows interoperability suite of programs for Linux. It implements the server message block (SMB) protocol. Modern versions of this protocol are also known as the common Internet file system (CIFS) protocol. It allows the networking of Microsoft Windows®, Linux, UNIX, and other operating systems together, enabling access to Windows-based file and printer shares. Samba's use of SMB allows it to appear as a Windows server to Windows clients.

Note

In order to use Samba, first ensure the samba package is installed on your system by running the following command as root: 
~]# yum install samba
For more information on installing packages with Yum, see Section 8.2.4, “Installing Packages”.

21.1.1. Introduction to Samba

Samba is an important component to seamlessly integrate Linux Servers and Desktops into Active Directory (AD) environments. It can function both as a domain controller (NT4-style) or as a regular domain member (AD or NT4-style).

What Samba can do:

  • Serve directory trees and printers to Linux, UNIX, and Windows clients
  • Assist in network browsing (with NetBIOS)
  • Authenticate Windows domain logins
  • Provide Windows Internet Name Service (WINS) name server resolution
  • Act as a Windows NT®-style Primary Domain Controller (PDC)
  • Act as a Backup Domain Controller (BDC) for a Samba-based PDC
  • Act as an Active Directory domain member server
  • Join a Windows NT/2000/2003/2008 PDC

What Samba cannot do:

  • Act as a BDC for a Windows PDC (and vice versa)
  • Act as an Active Directory domain controller

21.1.3. Connecting to a Samba Share

You can use either Nautilus or command line to connect to available Samba shares.

Procedure 21.1. Connecting to a Samba Share Using Nautilus

  1. To view a list of Samba workgroups and domains on your network, select Places Network from the GNOME panel, and then select the desired network. Alternatively, type smb: in the File Open Location bar of Nautilus.
    As shown in Figure 21.1, “SMB Workgroups in Nautilus”, an icon appears for each available SMB workgroup or domain on the network.
    SMB Workgroups in Nautilus

    Figure 21.1. SMB Workgroups in Nautilus

  2. Double-click one of the workgroup or domain icon to view a list of computers within the workgroup or domain.
    SMB Machines in Nautilus

    Figure 21.2. SMB Machines in Nautilus

  3. As displayed in Figure 21.2, “SMB Machines in Nautilus”, an icon exists for each machine within the workgroup. Double-click on an icon to view the Samba shares on the machine. If a user name and password combination is required, you are prompted for them.
    Alternately, you can also specify the Samba server and sharename in the Location: bar for Nautilus using the following syntax (replace servername and sharename with the appropriate values): 
    smb://servername/sharename

Procedure 21.2. Connecting to a Samba Share Using the Command Line

  1. To query the network for Samba servers, use the findsmb command. For each server found, it displays its IP address, NetBIOS name, workgroup name, operating system, and SMB server version: 
    findsmb
  2. To connect to a Samba share from a shell prompt, type the following command: 
    smbclient //hostname/sharename -U username
    Replace hostname with the host name or IP address of the Samba server you want to connect to, sharename with the name of the shared directory you want to browse, and username with the Samba user name for the system. Enter the correct password or press Enter if no password is required for the user.
    If you see the smb:\> prompt, you have successfully logged in. Once you are logged in, type help for a list of commands. If you want to browse the contents of your home directory, replace sharename with your user name. If the -U switch is not used, the user name of the current user is passed to the Samba server.
  3. To exit smbclient, type exit at the smb:\> prompt.

21.1.3.1. Mounting the Share

Sometimes it is useful to mount a Samba share to a directory so that the files in the directory can be treated as if they are part of the local file system.
To mount a Samba share to a directory, create a directory to mount it to (if it does not already exist), and execute the following command as root: 
mount -t cifs //servername/sharename /mnt/point/ -o username=username,password=password
This command mounts sharename from servername in the local directory /mnt/point/.
For more information about mounting a samba share, see the mount.cifs(8) manual page.

Note

The mount.cifs utility is a separate RPM (independent from Samba). In order to use mount.cifs, first ensure the cifs-utils package is installed on your system by running the following command as root: 
~]# yum install cifs-utils
For more information on installing packages with Yum, see Section 8.2.4, “Installing Packages”.
Note that the cifs-utils package also contains the cifs.upcall binary called by the kernel in order to perform kerberized CIFS mounts. For more information on cifs.upcall, see the cifs.upcall(8) manual page.

Warning

Some CIFS servers require plain text passwords for authentication. Support for plain text password authentication can be enabled using the following command as root: 
~]# echo 0x37 > /proc/fs/cifs/SecurityFlags
WARNING: This operation can expose passwords by removing password encryption.

21.1.4. Configuring a Samba Server

The default configuration file (/etc/samba/smb.conf) allows users to view their home directories as a Samba share. It also shares all printers configured for the system as Samba shared printers. You can attach a printer to the system and print to it from the Windows machines on your network.

21.1.4.1. Graphical Configuration

To configure Samba using a graphical interface, use one of the available Samba graphical user interfaces. A list of available GUIs can be found at http://www.samba.org/samba/GUI/.

21.1.4.2. Command-Line Configuration

Samba uses /etc/samba/smb.conf as its configuration file. If you change this configuration file, the changes do not take effect until you restart the Samba daemon with the following command as root: 
~]# service smb restart
To specify the Windows workgroup and a brief description of the Samba server, edit the following lines in your /etc/samba/smb.conf file: 
workgroup = WORKGROUPNAME
server string = BRIEF COMMENT ABOUT SERVER
Replace WORKGROUPNAME with the name of the Windows workgroup to which this machine should belong. The BRIEF COMMENT ABOUT SERVER is optional and is used as the Windows comment about the Samba system.
To create a Samba share directory on your Linux system, add the following section to your /etc/samba/smb.conf file (after modifying it to reflect your needs and your system):

Example 21.1. An Example Configuration of a Samba Server

[sharename]
comment = Insert a comment here
path = /home/share/
valid users = tfox carole
writable = yes
create mask = 0765
The above example allows the users tfox and carole to read and write to the directory /home/share/, on the Samba server, from a Samba client.

21.1.4.3. Encrypted Passwords

Encrypted passwords are enabled by default because it is more secure to use them. To create a user with an encrypted password, use the smbpasswd utility: 
smbpasswd -a username

21.1.5. Starting and Stopping Samba

To start a Samba server, type the following command in a shell prompt, as root: 
~]# service smb start

Important

To set up a domain member server, you must first join the domain or Active Directory using the net join command before starting the smb service. Also it is recommended to run winbind before smbd.
To stop the server, type the following command in a shell prompt, as root: 
~]# service smb stop
The restart option is a quick way of stopping and then starting Samba. This is the most reliable way to make configuration changes take effect after editing the configuration file for Samba. Note that the restart option starts the daemon even if it was not running originally.
To restart the server, type the following command in a shell prompt, as root: 
~]# service smb restart
The condrestart (conditional restart) option only stops and starts smb on the condition that it is currently running. This option is useful for scripts, because it does not start the daemon if it is not running.

Note

When the /etc/samba/smb.conf file is changed, Samba automatically reloads it after a few minutes. Issuing a manual restart or reload is just as effective.
To conditionally restart the server, type the following command as root: 
~]# service smb condrestart
A manual reload of the /etc/samba/smb.conf file can be useful in case of a failed automatic reload by the smb service. To ensure that the Samba server configuration file is reloaded without restarting the service, type the following command, as root: 
~]# service smb reload
By default, the smb service does not start automatically at boot time. To configure Samba to start at boot time, use an initscript utility, such as /sbin/chkconfig, /usr/sbin/ntsysv, or the Services Configuration Tool program. See Chapter 12, Services and Daemons for more information regarding these tools.

21.1.6. Samba Server Types and the smb.conf File

Samba configuration is straightforward. All modifications to Samba are done in the /etc/samba/smb.conf configuration file. Although the default smb.conf file is well documented, it does not address complex topics such as LDAP, Active Directory, and the numerous domain controller implementations.
The following sections describe the different ways a Samba server can be configured. Keep in mind your needs and the changes required to the /etc/samba/smb.conf file for a successful configuration.

21.1.6.1. Stand-alone Server

A stand-alone server can be a workgroup server or a member of a workgroup environment. A stand-alone server is not a domain controller and does not participate in a domain in any way. The following examples include several user-level security configurations. For more information on security modes, see Section 21.1.7, “Samba Security Modes”.

Anonymous Read-Only

The following /etc/samba/smb.conf file shows a sample configuration needed to implement anonymous read-only file sharing. Two directives are used to configure anonymous access – map to guest = Bad user and guest account = nobody.

Example 21.2. An Example Configuration of a Anonymous Read-Only Samba Server

[global]
workgroup = DOCS
netbios name = DOCS_SRV
security = user
guest account = nobody # default value
map to guest = Bad user

[data]
comment = Documentation Samba Server
path = /export
read only = yes
guest ok = yes

Anonymous Read/Write

The following /etc/samba/smb.conf file shows a sample configuration needed to implement anonymous read/write file sharing. To enable anonymous read/write file sharing, set the read only directive to no. The force user and force group directives are also added to enforce the ownership of any newly placed files specified in the share.

Note

Although having an anonymous read/write server is possible, it is not recommended. Any files placed in the share space, regardless of user, are assigned the user/group combination as specified by a generic user (force user) and group (force group) in the /etc/samba/smb.conf file.

Example 21.3. An Example Configuration of a Anonymous Read/Write Samba Server

[global]
workgroup = DOCS
security = user
guest account = nobody # default value
map to guest = Bad user

[data]
comment = Data
path = /export
guest ok = yes
writeable = yes
force user = user
force group = group

Anonymous Print Server

The following /etc/samba/smb.conf file shows a sample configuration needed to implement an anonymous print server. Setting browseable to no as shown does not list the printer in Windows Network Neighborhood. Although hidden from browsing, configuring the printer explicitly is possible. By connecting to DOCS_SRV using NetBIOS, the client can have access to the printer if the client is also part of the DOCS workgroup. It is also assumed that the client has the correct local printer driver installed, as the use client driver directive is set to yes. In this case, the Samba server has no responsibility for sharing printer drivers to the client.

Example 21.4. An Example Configuration of a Anonymous Print Samba Server

[global]
workgroup = DOCS
netbios name = DOCS_SRV
security = user
map to guest = Bad user
printing = cups

[printers]
comment = All Printers
path = /var/spool/samba
guest ok = yes
printable = yes
use client driver = yes
browseable = yes

Secure Read/Write File and Print Server

The following /etc/samba/smb.conf file shows a sample configuration needed to implement a secure read/write file and print server. Setting the security directive to user forces Samba to authenticate client connections. Notice the [homes] share does not have a force user or force group directive as the [public] share does. The [homes] share uses the authenticated user details for any files created as opposed to the force user and force group in [public].

Example 21.5. An Example Configuration of a Secure Read/Write File and Print Samba Server

[global]
workgroup = DOCS
netbios name = DOCS_SRV
security = user
printcap name = cups
disable spools = yes
show add printer wizard = no
printing = cups

[homes]
comment = Home Directories
valid users = %S
read only = no
browseable = no

[public]
comment = Data
path = /export
force user = docsbot
force group = users
guest ok = yes

[printers]
comment = All Printers
path = /var/spool/samba
printer admin = john, ed, @admins
create mask = 0600
guest ok = yes
printable = yes
use client driver = yes
browseable = yes

21.1.6.2. Domain Member Server

A domain member, while similar to a stand-alone server, is logged into a domain controller (either Windows or Samba) and is subject to the domain's security rules. An example of a domain member server would be a departmental server running Samba that has a machine account on the Primary Domain Controller (PDC). All of the department's clients still authenticate with the PDC, and desktop profiles and all network policy files are included. The difference is that the departmental server has the ability to control printer and network shares.

Active Directory Domain Member Server

To implement an Active Directory domain member server, follow procedure below:

Procedure 21.3. Adding a Member Server to an Active Directory Domain

  1. Create the /etc/samba/smb.conf configuration file on a member server to be added to the Active Directory domain. Add the following lines to the configuration file: 
    [global]
realm = EXAMPLE.COM
security = ADS
encrypt passwords = yes
# Optional. Use only if Samba cannot determine the Kerberos server automatically.
password server = kerberos.example.com
    With the above configuration, Samba authenticates users for services being run locally but is also a client of the Active Directory. Ensure that your kerberos realm parameter is shown in all caps (for example realm = EXAMPLE.COM). Since Windows 2000/2003/2008 requires Kerberos for Active Directory authentication, the realm directive is required. If Active Directory and Kerberos are running on different servers, the password server directive is required to help the distinction.
  2. Configure Kerberos on the member server. Create the /etc/krb5.conf configuration file with the following content: 
    [logging]
 default = FILE:/var/log/krb5libs.log

[libdefaults]
 default_realm = AD.EXAMPLE.COM
 dns_lookup_realm = true
 dns_lookup_kdc = true
 ticket_lifetime = 24h
 renew_lifetime = 7d
 rdns = false
 forwardable = false

[realms]
# Define only if DNS lookups are not working
# AD.EXAMPLE.COM = {
#  kdc = server.ad.example.com
#  admin_server = server.ad.example.com
#  master_kdc = server.ad.example.com
# }

[domain_realm]
# Define only if DNS lookups are not working
# .ad.example.com = AD.EXAMPLE.COM
# ad.example.com = AD.EXAMPLE.COM
    Uncomment the [realms] and [domain_realm] sections if DNS lookups are not working.
    For more information on Kerberos, and the /etc/krb5.conf file, see the Using Kerberos section of the Red Hat Enterprise Linux 6 Managing Single Sign-On and Smart Cards.
  3. To join an Active Directory server, type the following command as root on the member server: 
    ~]# net ads join -U administrator%password
    The net command authenticates as Administrator using the NT LAN Manager (NTLM) protocol and creates the machine account. Then net uses the machine account credentials to authenticate with Kerberos.

    Note

    Since security = ads and not security = user is used, a local password back end such as smbpasswd is not needed. Older clients that do not support security = ads are authenticated as if security = domain had been set. This change does not affect functionality and allows local users not previously in the domain.

Windows NT4-based Domain Member Server

The following /etc/samba/smb.conf file shows a sample configuration needed to implement a Windows NT4-based domain member server. Becoming a member server of an NT4-based domain is similar to connecting to an Active Directory. The main difference is NT4-based domains do not use Kerberos in their authentication method, making the /etc/samba/smb.conf file simpler. In this instance, the Samba member server functions as a pass through to the NT4-based domain server.

Example 21.6. An Example Configuration of Samba Windows NT4-based Domain Member Server

[global]
workgroup = DOCS
netbios name = DOCS_SRV
security = domain

[homes]
comment = Home Directories
valid users = %S
read only = no
browseable = no

[public]
comment = Data
path = /export
force user = docsbot
force group = users
guest ok = yes
Having Samba as a domain member server can be useful in many situations. There are times where the Samba server can have other uses besides file and printer sharing. It may be beneficial to make Samba a domain member server in instances where Linux-only applications are required for use in the domain environment. Administrators appreciate keeping track of all machines in the domain, even if not Windows-based. In the event the Windows-based server hardware is deprecated, it is quite easy to modify the /etc/samba/smb.conf file to convert the server to a Samba-based PDC. If Windows NT-based servers are upgraded to Windows 2000/2003/2008 the /etc/samba/smb.conf file is easily modifiable to incorporate the infrastructure change to Active Directory if needed.

Important

After configuring the /etc/samba/smb.conf file, join the domain before starting Samba by typing the following command as root: 
~]# net rpc join -U administrator%password
Note that the -S option, which specifies the domain server host name, does not need to be stated in the net rpc join command. Samba uses the host name specified by the workgroup directive in the /etc/samba/smb.conf file instead of it being stated explicitly.

21.1.6.3. Domain Controller

A domain controller in Windows NT is functionally similar to a Network Information Service (NIS) server in a Linux environment. Domain controllers and NIS servers both host user and group information databases as well as related services. Domain controllers are mainly used for security, including the authentication of users accessing domain resources. The service that maintains the user and group database integrity is called the Security Account Manager (SAM). The SAM database is stored differently between Windows and Linux Samba-based systems, therefore SAM replication cannot be achieved and platforms cannot be mixed in a PDC/BDC environment.
In a Samba environment, there can be only one PDC and zero or more BDCs.

Important

Samba cannot exist in a mixed Samba/Windows domain controller environment (Samba cannot be a BDC of a Windows PDC or vice versa). Alternatively, Samba PDCs and BDCs can coexist.

Primary Domain Controller (PDC) Using tdbsam

The simplest and most common implementation of a Samba PDC uses the new default tdbsam password database back end. Replacing the aging smbpasswd back end, tdbsam has numerous improvements that are explained in more detail in Section 21.1.8, “Samba Account Information Databases”. The passdb backend directive controls which back end is to be used for the PDC.
The following /etc/samba/smb.conf file shows a sample configuration needed to implement a tdbsam password database back end.

Example 21.7. An Example Configuration of Primary Domain Controller (PDC) Using tdbsam

[global]
workgroup = DOCS
netbios name = DOCS_SRV
passdb backend = tdbsam
security = user
add user script = /usr/sbin/useradd -m "%u"
delete user script = /usr/sbin/userdel -r "%u"
add group script = /usr/sbin/groupadd "%g"
delete group script = /usr/sbin/groupdel "%g"
add user to group script = /usr/sbin/usermod -G "%g" "%u"
add machine script = /usr/sbin/useradd -s /bin/false -d /dev/null  -g machines "%u"
# The following specifies the default logon script
# Per user logon scripts can be specified in the user
# account using pdbedit logon script = logon.bat
# This sets the default profile path.
# Set per user paths with pdbedit
logon drive = H:
domain logons = yes
os level = 35
preferred master = yes
domain master = yes

[homes]
	comment = Home Directories
	valid users = %S
	read only = no
	
[netlogon]
	comment = Network Logon Service
	path = /var/lib/samba/netlogon/scripts
	browseable = no
	read only = no
# For profiles to work, create a user directory under the
# path shown.
# mkdir -p /var/lib/samba/profiles/john

[Profiles]
	comment = Roaming Profile Share
	path = /var/lib/samba/profiles
	read only = no
	browseable = no
	guest ok = yes
	profile acls = yes
# Other resource shares ... ...
To provide a functional PDC system which uses tdbsam follow these steps:
  1. Adjust the smb.conf configuration file as shown in Example 21.7, “An Example Configuration of Primary Domain Controller (PDC) Using tdbsam”.
  2. Add the root user to the Samba password database. You will be prompted to provide a new Samba password for the root user: 
    ~]# smbpasswd -a root
New SMB password:
  3. Start the smb service: 
    ~]# service smb start
  4. Make sure all profile, user, and netlogon directories are created.
  5. Add groups that users can be members of: 
    ~]# groupadd -f users
~]# groupadd -f nobody
~]# groupadd -f ntadmins
  6. Associate the UNIX groups with their respective Windows groups. 
    ~]# net groupmap add ntgroup="Domain Users" unixgroup=users
~]# net groupmap add ntgroup="Domain Guests" unixgroup=nobody
~]# net groupmap add ntgroup="Domain Admins" unixgroup=ntadmins
  7. Grant access rights to a user or a group. For example, to grant the right to add client machines to the domain on a Samba domain controller, to the members to the Domain Admins group, execute the following command: 
    ~]# net rpc rights grant 'DOCS\Domain Admins' SetMachineAccountPrivilege -S PDC -U root
Keep in mind that Windows systems prefer to have a primary group which is mapped to a domain group such as Domain Users.
Windows groups and users use the same namespace thus not allowing the existence of a group and a user with the same name like in UNIX.

Note

If you need more than one domain controller or have more than 250 users, do not use the tdbsam authentication back end. LDAP is recommended in these cases.

Primary Domain Controller (PDC) with Active Directory

Although it is possible for Samba to be a member of an Active Directory, it is not possible for Samba to operate as an Active Directory domain controller.

21.1.7. Samba Security Modes

There are only two types of security modes for Samba, share-level and user-level, which are collectively known as security levels. Share-level security is deprecated and Red Hat recommends to use user-level security instead. User-level security can be implemented in one of three different ways. The different ways of implementing a security level are called security modes.

21.1.7.1. User-Level Security

User-level security is the default and recommended setting for Samba. Even if the security = user directive is not listed in the /etc/samba/smb.conf file, it is used by Samba. If the server accepts the client's user name and password, the client can then mount multiple shares without specifying a password for each instance. Samba can also accept session-based user name and password requests. The client maintains multiple authentication contexts by using a unique UID for each logon.
In the /etc/samba/smb.conf file, the security = user directive that sets user-level security is: 
[GLOBAL]
...
security = user
...

Samba Guest Shares

As mentioned above, share-level security mode is deprecated and highly recommended to not use. To configure a Samba guest share without using the security = share parameter, follow the procedure below:

Procedure 21.4. Configuring Samba Guest Shares

  1. Create a username map file, in this example /etc/samba/smbusers, and add the following line to it: 
    nobody = guest
  2. Add the following directives to the main section in the /etc/samba/smb.conf file. Also, do not use the valid users directive: 
    [GLOBAL]
...
security = user
map to guest = Bad User
username map = /etc/samba/smbusers
...
    The username map directive provides a path to the username map file specified in the previous step.
  3. Add the following directive to the share section in the /ect/samba/smb.conf file. Do not use the valid users directive. 
    [SHARE]
...
guest ok = yes
...
The following sections describe other implementations of user-level security.

Domain Security Mode (User-Level Security)

In domain security mode, the Samba server has a machine account (domain security trust account) and causes all authentication requests to be passed through to the domain controllers. The Samba server is made into a domain member server by using the following directives in the /etc/samba/smb.conf file: 
[GLOBAL]
...
security = domain
workgroup = MARKETING
...

Active Directory Security Mode (User-Level Security)

If you have an Active Directory environment, it is possible to join the domain as a native Active Directory member. Even if a security policy restricts the use of NT-compatible authentication protocols, the Samba server can join an ADS using Kerberos. Samba in Active Directory member mode can accept Kerberos tickets.
In the /etc/samba/smb.conf file, the following directives make Samba an Active Directory member server: 
[GLOBAL]
...
security = ADS
realm = EXAMPLE.COM
password server = kerberos.example.com
...

21.1.7.2. Share-Level Security

With share-level security, the server accepts only a password without an explicit user name from the client. The server expects a password for each share, independent of the user name. There have been recent reports that Microsoft Windows clients have compatibility issues with share-level security servers. This mode is deprecated and Red Hat strongly discourage use of share-level security. Follow steps in Procedure 21.4, “Configuring Samba Guest Shares” instead of using the security = share directive.

21.1.8. Samba Account Information Databases

The following is a list different back ends you can use with Samba. Other back ends not listed here may also be available.
Plain Text
Plain text back ends are nothing more than the /etc/passwd type back ends. With a plain text back end, all user names and passwords are sent unencrypted between the client and the Samba server. This method is very insecure and is not recommended for use by any means. It is possible that different Windows clients connecting to the Samba server with plain text passwords cannot support such an authentication method.
smbpasswd
The smbpasswd back end utilizes a plain ASCII text layout that includes the MS Windows LanMan and NT account, and encrypted password information. The smbpasswd back end lacks the storage of the Windows NT/2000/2003 SAM extended controls. The smbpasswd back end is not recommended because it does not scale well or hold any Windows information, such as RIDs for NT-based groups. The tdbsam back end solves these issues for use in a smaller database (250 users), but is still not an enterprise-class solution.
ldapsam_compat
The ldapsam_compat back end allows continued OpenLDAP support for use with upgraded versions of Samba.
tdbsam
The default tdbsam password back end provides a database back end for local servers, servers that do not need built-in database replication, and servers that do not require the scalability or complexity of LDAP. The tdbsam back end includes all of the smbpasswd database information as well as the previously-excluded SAM information. The inclusion of the extended SAM data allows Samba to implement the same account and system access controls as seen with Windows NT/2000/2003/2008-based systems.
The tdbsam back end is recommended for 250 users at most. Larger organizations should require Active Directory or LDAP integration due to scalability and possible network infrastructure concerns.
ldapsam
The ldapsam back end provides an optimal distributed account installation method for Samba. LDAP is optimal because of its ability to replicate its database to any number of servers such as the Red Hat Directory Server or an OpenLDAP Server. LDAP databases are light-weight and scalable, and as such are preferred by large enterprises. Installation and configuration of directory servers is beyond the scope of this chapter. For more information on the Red Hat Directory Server, see the Red Hat Directory Server 9.0 Deployment Guide. For more information on LDAP, see Section 20.1, “OpenLDAP”.
If you are upgrading from a previous version of Samba to 3.0, note that the OpenLDAP schema file (/usr/share/doc/samba-version/LDAP/samba.schema) and the Red Hat Directory Server schema file (/usr/share/doc/samba-version/LDAP/samba-schema-FDS.ldif) have changed. These files contain the attribute syntax definitions and objectclass definitions that the ldapsam back end needs in order to function properly.
As such, if you are using the ldapsam back end for your Samba server, you will need to configure slapd to include one of these schema file. See Section 20.1.3.3, “Extending Schema” for directions on how to do this.

Note

You need to have the openldap-servers package installed if you want to use the ldapsam back end. To ensure that the package is installed, execute the following command as roots: 
~]# yum install openldap-servers

21.1.9. Samba Network Browsing

Network browsing enables Windows and Samba servers to appear in the Windows Network Neighborhood. Inside the Network Neighborhood, icons are represented as servers and if opened, the server's shares and printers that are available are displayed.
Network browsing capabilities require NetBIOS over TCP/IP. NetBIOS-based networking uses broadcast (UDP) messaging to accomplish browse list management. Without NetBIOS and WINS as the primary method for TCP/IP host name resolution, other methods such as static files (/etc/hosts) or DNS, must be used.
A domain master browser collates the browse lists from local master browsers on all subnets so that browsing can occur between workgroups and subnets. Also, the domain master browser should preferably be the local master browser for its own subnet.

21.1.9.1. Domain Browsing

By default, a Windows server PDC for a domain is also the domain master browser for that domain. A Samba server must not be set up as a domain master server in this type of situation.
For subnets that do not include the Windows server PDC, a Samba server can be implemented as a local master browser. Configuring the /etc/samba/smb.conf file for a local master browser (or no browsing at all) in a domain controller environment is the same as workgroup configuration (see Section 21.1.4, “Configuring a Samba Server”).

21.1.9.2. WINS (Windows Internet Name Server)

Either a Samba server or a Windows NT server can function as a WINS server. When a WINS server is used with NetBIOS enabled, UDP unicasts can be routed which allows name resolution across networks. Without a WINS server, the UDP broadcast is limited to the local subnet and therefore cannot be routed to other subnets, workgroups, or domains. If WINS replication is necessary, do not use Samba as your primary WINS server, as Samba does not currently support WINS replication.
In a mixed NT/2000/2003/2008 server and Samba environment, it is recommended that you use the Microsoft WINS capabilities. In a Samba-only environment, it is recommended that you use only one Samba server for WINS.
The following is an example of the /etc/samba/smb.conf file in which the Samba server is serving as a WINS server:

Example 21.8. An Example Configuration of WINS Server

[global]
wins support = yes

Note

All servers (including Samba) should connect to a WINS server to resolve NetBIOS names. Without WINS, browsing only occurs on the local subnet. Furthermore, even if a domain-wide list is somehow obtained, hosts cannot be resolved for the client without WINS.

21.1.10. Samba with CUPS Printing Support

Samba allows client machines to share printers connected to the Samba server. In addition, Samba also allows client machines to send documents built in Linux to Windows printer shares. Although there are other printing systems that function with Red Hat Enterprise Linux, CUPS (Common UNIX Print System) is the recommended printing system due to its close integration with Samba.

21.1.10.1. Simple smb.conf Settings

The following example shows a very basic /etc/samba/smb.conf configuration for CUPS support:

Example 21.9. An Example Configuration of Samba with CUPS Support

[global]
load printers = yes
printing = cups
printcap name = cups
[printers]
comment = All Printers
path = /var/spool/samba
browseable = no
guest ok = yes
writable = no
printable = yes
printer admin = @ntadmins
[print$]
comment = Printer Drivers Share
path = /var/lib/samba/drivers
write list = ed, john
printer admin = ed, john
Other printing configurations are also possible. To add additional security and privacy for printing confidential documents, users can have their own print spooler not located in a public path. If a job fails, other users would not have access to the file.
The print$ directive contains printer drivers for clients to access if not available locally. The print$ directive is optional and may not be required depending on the organization.
Setting browseable to yes enables the printer to be viewed in the Windows Network Neighborhood, provided the Samba server is set up correctly in the domain or workgroup.

21.1.11. Samba Distribution Programs

findsmb

findsmb <subnet_broadcast_address>
The findsmb program is a Perl script which reports information about SMB-aware systems on a specific subnet. If no subnet is specified the local subnet is used. Items displayed include IP address, NetBIOS name, workgroup or domain name, operating system, and version. The findsmb command is used in the following format:
The following example shows the output of executing findsmb as any valid user on a system: 
~]$ findsmb
IP ADDR       NETBIOS NAME  WORKGROUP/OS/VERSION
------------------------------------------------------------------
10.1.59.25    VERVE         [MYGROUP] [Unix] [Samba 3.0.0-15]
10.1.59.26    STATION22     [MYGROUP] [Unix] [Samba 3.0.2-7.FC1]
10.1.56.45    TREK         +[WORKGROUP] [Windows 5.0] [Windows 2000 LAN Manager]
10.1.57.94    PIXEL         [MYGROUP] [Unix] [Samba 3.0.0-15]
10.1.57.137   MOBILE001     [WORKGROUP] [Windows 5.0] [Windows 2000 LAN Manager]
10.1.57.141   JAWS         +[KWIKIMART] [Unix] [Samba 2.2.7a-security-rollup-fix]
10.1.56.159   FRED         +[MYGROUP] [Unix] [Samba 3.0.0-14.3E]
10.1.59.192   LEGION       *[MYGROUP] [Unix] [Samba 2.2.7-security-rollup-fix]
10.1.56.205   NANCYN       +[MYGROUP] [Unix] [Samba 2.2.7a-security-rollup-fix]

net

net <protocol> <function> <misc_options> <target_options>
The net utility is similar to the net utility used for Windows and MS-DOS. The first argument is used to specify the protocol to use when executing a command. The protocol option can be ads, rap, or rpc for specifying the type of server connection. Active Directory uses ads, Win9x/NT3 uses rap, and Windows NT4/2000/2003/2008 uses rpc. If the protocol is omitted, net automatically tries to determine it.
The following example displays a list of the available shares for a host named wakko: 
~]$ net -l share -S wakko
Password:
Enumerating shared resources (exports) on remote server:
Share name   Type     Description
----------   ----     -----------
data         Disk     Wakko data share
tmp          Disk     Wakko tmp share
IPC$         IPC      IPC Service (Samba Server)
ADMIN$       IPC      IPC Service (Samba Server)
The following example displays a list of Samba users for a host named wakko: 
~]$ net -l user -S wakko
root password:
User name             Comment
-----------------------------
andriusb              Documentation
joe                   Marketing
lisa                  Sales

nmblookup

nmblookup <options> <netbios_name>
The nmblookup program resolves NetBIOS names into IP addresses. The program broadcasts its query on the local subnet until the target machine replies.
The following example displays the IP address of the NetBIOS name trek: 
~]$ nmblookup trek
querying trek on 10.1.59.255
10.1.56.45 trek<00>

pdbedit

pdbedit <options>
The pdbedit program manages accounts located in the SAM database. All back ends are supported including smbpasswd, LDAP, and the tdb database library.
The following are examples of adding, deleting, and listing users: 
~]$ pdbedit -a kristin
new password:
retype new password:
Unix username:        kristin
NT username:
Account Flags:        [U          ]
User SID:             S-1-5-21-1210235352-3804200048-1474496110-2012
Primary Group SID:    S-1-5-21-1210235352-3804200048-1474496110-2077
Full Name: Home Directory:       \\wakko\kristin
HomeDir Drive:
Logon Script:
Profile Path:         \\wakko\kristin\profile
Domain:               WAKKO
Account desc:
Workstations: Munged
dial:
Logon time:           0
Logoff time:          Mon, 18 Jan 2038 22:14:07 GMT
Kickoff time:         Mon, 18 Jan 2038 22:14:07 GMT
Password last set:    Thu, 29 Jan 2004 08:29:28
GMT Password can change:  Thu, 29 Jan 2004 08:29:28 GMT
Password must change: Mon, 18 Jan 2038 22:14:07 GMT
~]$ pdbedit -v -L kristin
Unix username:        kristin
NT username:
Account Flags:        [U          ]
User SID:             S-1-5-21-1210235352-3804200048-1474496110-2012
Primary Group SID:    S-1-5-21-1210235352-3804200048-1474496110-2077
Full Name:
Home Directory:       \\wakko\kristin
HomeDir Drive:
Logon Script:
Profile Path:         \\wakko\kristin\profile
Domain:               WAKKO
Account desc:
Workstations: Munged
dial:
Logon time:           0
Logoff time:          Mon, 18 Jan 2038 22:14:07 GMT
Kickoff time:         Mon, 18 Jan 2038 22:14:07 GMT
Password last set:    Thu, 29 Jan 2004 08:29:28 GMT
Password can change:  Thu, 29 Jan 2004 08:29:28 GMT
Password must change: Mon, 18 Jan 2038 22:14:07 GMT
~]$ pdbedit -L
andriusb:505:
joe:503:
lisa:504:
kristin:506:
~]$ pdbedit -x joe
~]$ pdbedit -L
andriusb:505: lisa:504: kristin:506:

rpcclient

rpcclient <server> <options>
The rpcclient program issues administrative commands using Microsoft RPCs, which provide access to the Windows administration graphical user interfaces (GUIs) for systems management. This is most often used by advanced users that understand the full complexity of Microsoft RPCs.

smbcacls

smbcacls <//server/share> <filename> <options>
The smbcacls program modifies Windows ACLs on files and directories shared by a Samba server or a Windows server.

smbclient

smbclient <//server/share> <password> <options>
The smbclient program is a versatile UNIX client which provides functionality similar to the ftp utility.

smbcontrol

smbcontrol -i <options>
smbcontrol <options> <destination> <messagetype> <parameters>
The smbcontrol program sends control messages to running smbd, nmbd, or winbindd daemons. Executing smbcontrol -i runs commands interactively until a blank line or a 'q' is entered.

smbpasswd

smbpasswd <options> <username> <password>
The smbpasswd program manages encrypted passwords. This program can be run by a superuser to change any user's password and also by an ordinary user to change their own Samba password.

smbspool

smbspool <job> <user> <title> <copies> <options> <filename>
The smbspool program is a CUPS-compatible printing interface to Samba. Although designed for use with CUPS printers, smbspool can work with non-CUPS printers as well.

smbstatus

smbstatus <options>
The smbstatus program displays the status of current connections to a Samba server.

smbtar

smbtar <options>
The smbtar program performs backup and restores of Windows-based share files and directories to a local tape archive. Though similar to the tar utility, the two are not compatible.

testparm

testparm <options> <filename> <hostname IP_address>
The testparm program checks the syntax of the /etc/samba/smb.conf file. If your smb.conf file is in the default location (/etc/samba/smb.conf) you do not need to specify the location. Specifying the host name and IP address to the testparm program verifies that the hosts.allow and host.deny files are configured correctly. The testparm program also displays a summary of your smb.conf file and the server's role (stand-alone, domain, etc.) after testing. This is convenient when debugging as it excludes comments and concisely presents information for experienced administrators to read. For example: 
~]$ testparm
Load smb config files from /etc/samba/smb.conf
Processing section "[homes]"
Processing section "[printers]"
Processing section "[tmp]"
Processing section "[html]"
Loaded services file OK.
Server role: ROLE_STANDALONE
Press enter to see a dump of your service definitions
<enter>
# Global parameters
[global]
	workgroup = MYGROUP
	server string = Samba Server
	security = SHARE
	log file = /var/log/samba/%m.log
	max log size = 50
	socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192
	dns proxy = no
[homes]
	comment = Home Directories
	read only = no
	browseable = no
[printers]
	comment = All Printers
	path = /var/spool/samba
	printable = yes
	browseable = no
[tmp]
	comment = Wakko tmp
	path = /tmp
	guest only = yes
[html]
	comment = Wakko www
	path = /var/www/html
	force user = andriusb
	force group = users
	read only = no
	guest only = yes

wbinfo

wbinfo <options>
The wbinfo program displays information from the winbindd daemon. The winbindd daemon must be running for wbinfo to work.

21.1.12. Additional Resources

The following sections give you the means to explore Samba in greater detail.

Installed Documentation

  • /usr/share/doc/samba-<version-number>/ — All additional files included with the Samba distribution. This includes all helper scripts, sample configuration files, and documentation.
  • See the following man pages for detailed information specific Samba features:
    • smb.conf(5)
    • samba(7)
    • smbd(8)
    • nmbd(8)
    • winbindd(8)
  • The Official Samba-3 HOWTO-Collection by John H. Terpstra and Jelmer R. Vernooij; Prentice Hall — The official Samba-3 documentation as issued by the Samba development team. This is more of a reference guide than a step-by-step guide.
  • Samba-3 by Example by John H. Terpstra; Prentice Hall — This is another official release issued by the Samba development team which discusses detailed examples of OpenLDAP, DNS, DHCP, and printing configuration files. This has step-by-step related information that helps in real-world implementations.
  • Using Samba, 2nd Edition by Jay Ts, Robert Eckstein, and David Collier-Brown; O'Reilly — A good resource for novice to advanced users, which includes comprehensive reference material.

Useful Websites

  • http://www.samba.org/ — Homepage for the Samba distribution and all official documentation created by the Samba development team. Many resources are available in HTML and PDF formats, while others are only available for purchase. Although many of these links are not Red Hat Enterprise Linux specific, some concepts may apply.
  • http://samba.org/samba/archives.html — Active email lists for the Samba community. Enabling digest mode is recommended due to high levels of list activity.
  • Samba newsgroups — Samba threaded newsgroups, such as www.gmane.org, that use the NNTP protocol are also available. This an alternative to receiving mailing list emails.
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