Samba and Samba Client
Samba allows both RHEL resources to be shared with Windows systems
and Windows resources to be shared with RHEL systems. RHEL accesses Windows
resources using a package named samba-client. RHEL resources, on the other
hand, are shared with Windows systems using a package named samba. Typically,
the samba-client is installed and configured by default allowing you to browse
available Windows resources without any additional work (this is covered later
in the chapter). In order to allow an RHEL 6 system to share resources with
Windows systems, however, some more work is required.
The default settings used during the RHEL 6 installation process
do not install the samba package. Unless you specifically requested that Samba
be installed it is unlikely that you have Samba installed on your system. To
check whether Samba is installed, open a terminal window (Applications ->
System Tools -> Terminal) and run the following rpm command:
rpm
-q samba
If Samba is installed, the rpm command will generate output
similar to the following:
samba-3.5.4-68.el6_0.1.x86_64
If Samba is not installed, rpm will return with "package
samba is not installed". That being the case, it can be installed using
the yum command-line tool:
su
-
yum
install samba
The above command will install both the samba package and the
samba-common dependency package.
If you prefer to use the graphical tool to perform the Samba
installation, select Applications -> Add/Remove Software, enter
the root password if prompted to do so and then perform a search for Samba.
When the list of matching packages appears, set the checkbox next to the samba
and samba-common packages and click on Apply to initiate the
installation.
Next, the firewall currently protecting the RHEL system needs to
be configured to allow Samba traffic. To achieve this, run the Firewall
Configuration tool by selecting the System -> Administration ->
Firewall menu option and select the check box next to Samba in the
Trusted Services section of the tool. Click Apply and OK to commit the change.
Before any resources on the RHEL system can be accessed from the
Windows systems, however, some additional configuration steps are necessary.
In releases of Red Hat Enterprise Linux prior to release 6, a user
friendly graphical tool named system-config-samba was provided
to assist in the configuration of Samba. In RHEL 6, however, this tool has been
removed. This means that the Samba environment must be configured manually
within the /etc/samba/smb.conf file and using the smbpasswd command
line tool. Whilst the loss of system-config-samba may be
mourned by those who relied on it, the tool’s simplicity actually masked many
of the more advanced features of Samba. In practice, much more can be achieved
by tasking the time to understand the intricacies of the smb.conf file.
Samba is a highly flexible and configurable system that provides
many different options for controlling how resources are shared on Windows
networks. This flexibility can lead to the sense that Samba is overly complex
to work with. In reality, however, many of the configuration options are not
needed by the typical installation, and the learning curve to set up a basic
configuration is actually quite short.
For the purposes of this chapter we will look at joining an RHEL 6
system to a Windows workgroup and setting up a directory as a shared resource
that can be accessed by a specific user.
The first step, therefore, is to gain root privileges and to load
the /etc/samba/smb.conf file into a suitable editor, for
example:
su
–
gedit
/etc/samba/smb.conf
The smb.conf file is divided into sections. The first section is
the [global] section where settings can be specified that apply to the entire
Samba configuration. Whilst these settings are global, each option may be
overridden within other sections of the configuration file.
The first task is to define the name of the Windows workgroup on
which the RHEL 6 resources are to be shared. This is controlled via the
workgroup = directive of the [global] section which by default is configured as
follows:
workgroup
= MYGROUP
Begin by changing this to the actual name of the workgroup. For
example, if the workgroup is named WORKGROUP (the default for most Windows
networks):
workgroup
= workgroup
The next step is to configure a shared resource (in other words a
resource that will be accessible from other systems on the Windows network). In
order to achieve this, the section is given a name by which it will be referred
to when shared. For example, if we plan to share the /tmp directory of our RHEL
6 system, we might entitle the section [tmp]. In this section a variety of
configuration options are possible. For the purposes of this example, however,
we will simply define the directory that is to be shared, indicate that the
directory is browsable and writable and declare the users that are allowed to access
the shared resource (in this case a user named demo):
[tmp]
path = /tmp
writeable = yes
browseable = yes
valid users = demo
Any user that requires access to a Samba shared resource must be
configured as a Samba User and assigned a password. This task
is achieved using the smbpasswd command line tool. In our
example smb.conf file we stated the user demo is entitled to access the /tmp
directory of our RHEL 6 system. In order to fulfill this requirement,
therefore, we must add demo as a samba user as follows:
#
su -
#
smbpasswd -a demo
New
SMB password:
Retype
new SMB password:
Added
user demo.
Now that we have completed the configuration of a very basic Samba
server, it is time to test our configuration file and then start the Samba
services.
The settings in the smb.conf file may be tested using the testparm
command line tool as follows:
#
testparm
Load
smb config files from /etc/samba/smb.conf
rlimit_max:
rlimit_max (1024) below minimum Windows limit (16384)
Processing
section "[homes]"
Processing
section "[printers]"
Processing
section "[tmp]"
Loaded
services file OK.
Server
role: ROLE_STANDALONE
Press
enter to see a dump of your service definitions
[global]
server string = Samba Server Version %v
log file = /var/log/samba/log.%m
max log size = 50
cups options = raw
[homes]
comment = Home Directories
read only = No
browseable = No
[printers]
comment = All Printers
path = /var/spool/samba
printable = Yes
browseable = No
[tmp]
path = /tmp
valid users = demo
read only = No
In order for an RHEL 6 server to operate within a Windows network
both the Samba (SMB) and NetBOIS nameservice (NMB) services must be started. To
identify if the services are already running, the following command may be
executed with root privileges in a terminal window:
su
–
/sbin/service
smb status
smbd
is stopped
#
/sbin/service nmb status
nmbd
is stopped
If the services are reported as currently running and you have
made changes to the smb.conf file it will be necessary to restart the services
in order to pick up the changes:
/sbin/service
smb restart
/sbin/service
nmb restart
If, on the other hand, the services are currently stopped, start
them as follows:
/sbin/service
smb start
/sbin/service
nmb start
Now that the Samba resources are configured and the services are
running, it is time to access the shared resource from a Windows system. On a
suitable Windows system on the same workgroup as the RHEL 6 system, open
Windows Explorer and navigate to the Network page. At this point, explorer
should search the network and list any systems using the SMB protocol that it
finds. The following figure illustrates an RHEL 6 system named rhel6 located
using Windows Explorer on a Windows 7 system:
Double clicking on the RHEL 6 host will prompt for the name and password of a user with access privileges. In this case it is the demo account that we configured using the smbpasswd tool. Entering the username and password will result in the shared resources configured for that user appearing the explorer window, including the tmp resource previously configured:
Double clicking on the tmp shred resource will display a listing of the files and directories contained therein.
As previously mentioned, Samba is a two way street, allowing not
only Windows systems to access files and printers hosted on an RHEL 6 system,
but also allowing the RHEL system to access shared resources on Windows
systems. This is achieved using the samba-client package which is installed by
default under most RHEL 6 configurations. If it is not currently installed,
install it from a Terminal window as follows:
su
–
yum
install samba-client
To access any shared resources on a Windows system, begin by selecting
the Places -> Network desktop menu option. This will
display the Network browser dialog including an icon for the Windows
Network (if one is detected) as illustrated in the following figure:
To obtain a list of Windows workgroups on the network, double click on the Windows Network icon. From within the list of workgroups double click on the desired group to obtain a listing of servers available for access:
Finally, double clicking on a computer will list the shared resources available for access from the RHEL client.
In this chapter we have looked at the steps necessary to configure
an RHEL 6 system to act as both a Samba client and server allowing the sharing
of resources with other systems on a Windows based network. In the case of
Samba server configuration in particular we have only scratched the surface of
the configuration options available. A full over of Samba would require an
entire book. Many such publications and online resources are available if you
would like to learn more. Another good place to start is to type man
samba in a terminal window.
