Translations by Patrick Rau

Ubuntu Server Guide

Windows Networking

Computer networks are often comprised of diverse systems, and while operating a network made up entirely of Ubuntu desktop and server computers would certainly be fun, some network environments must consist of both Ubuntu and <trademark class="registered">Microsoft</trademark><trademark class="registered">Windows</trademark> systems working together in harmony. This section of the <phrase>Ubuntu</phrase> Server Guide introduces principles and tools used in configuring your Ubuntu Server for sharing network resources with Windows computers.

Introduction

Successfully networking your Ubuntu system with Windows clients involves providing and integrating with services common to Windows environments. Such services assist the sharing of data and information about the computers and users involved in the network, and may be classified under three major categories of functionality:

<emphasis role="bold">File and Printer Sharing Services</emphasis>. Using the Server Message Block (SMB) protocol to facilitate the sharing of files, folders, volumes, and the sharing of printers throughout the network.

<emphasis role="bold">Directory Services</emphasis>. Sharing vital information about the computers and users of the network with such technologies as the Lightweight Directory Access Protocol (LDAP) and Microsoft <trademark class="registered">Active Directory</trademark>.

Fortunately, your Ubuntu system may provide all such facilities to Windows clients and share network resources among them. One of the principle pieces of software your Ubuntu system includes for Windows networking is the SAMBA suite of SMB server applications and tools. This section of the <phrase>Ubuntu</phrase> Server Guide will briefly introduce the installation and limited configuration of the SAMBA suite of server applications and utilities. Additional, detailed documentation and information on SAMBA is beyond the scope of this documentation, but exists on the <ulink url="http://www.samba.org">SAMBA website</ulink>.

You may configure the SAMBA server by editing the <filename>/etc/samba/smb.conf</filename> file to change the default settings or add new settings. More information about each setting is available in the comments of the <filename>/etc/samba/smb.conf</filename> file or by viewing the <filename>/etc/samba/smb.conf</filename> manual page from the prompt with the following command typed at a terminal prompt:

Prior to editing the configuration file, you should make a copy of the original file and protect it from writing so you will have the original settings as a reference and to re-use as necessary.

Backup the <filename>/etc/samba/smb.conf</filename> file:

Now, edit the <filename>/etc/samba/smb.conf</filename> file and make your changes.

The following sections will discuss SAMBA and the supporting technologies, such as Lightweight Directory Access Protocol (LDAP) server, and Kerberos authentication server in more detail. You will also learn about some of the available configuration directives available the SAMBA configuration file which facilitate network integration with Windows clients and servers.

Active Directory is a proprietary implementation of Directory Services by Microsoft, and is used to provide a means to share information about network resources and users. In addition to providing a centralized source of such information, Active Directory also acts as a centralized authentication security authority for the network. Active directory combines capabilities traditionally found in separate, specialized directory systems to simplify integration, management, and security of network resources. The SAMBA package may be configured to use Active Directory services from a Windows Domain Controller.

realm = DOMAIN_NAME

security = ADS

to the file, and save the file.

Be sure to replace the token DOMAIN_NAME in the example above with the actual name of your specific Windows Domain.

Computer Accounts

Computer Accounts are used in Directory Services to uniquely identify computer systems participating in a network, and are even treated in the same manner as users in terms of security. Computer accounts may have passwords just as user accounts do, and are subject to authorization to network resources in the same manner as user accounts. For example, if a network user, with a valid account for a particular network attempts to authenticate with a network resource from a computer which does not have a valid computer account, depending upon policies enforced on the network, the user may be denied access to the resource if the computer the user is attempting authentication from is considered to be an unauthorized computer.

A computer account may be added to the SAMBA password file, provided the name of the computer being added exists as a valid user account in the local password database first. The syntax for adding a computer or machine account to the SAMBA password file is to use the <application>smbpasswd</application> command from a terminal prompt as follows:

Be sure to replace the token COMPUTER_NAME in the example above with the actual name of the specific computer you wish to add a machine account for.

File Permissions define the explicit rights a computer or user has to a particular directory, file, or set of files. Such permissions may be defined by editing the <filename>/etc/samba/smb.conf</filename> file and specifying the explicit permissions of a defined file share. For example, if you have defined a SAMBA share called <emphasis role="italic">sourcedocs</emphasis> and wish to give <emphasis role="italic">read-only</emphasis> permissions to the group of users known as <emphasis role="italic">planning</emphasis>, but wanted to allow writing to the share by the group called <emphasis role="italic">authors</emphasis> and the user named <emphasis role="italic">richard</emphasis>, then you could edit the <filename>/etc/samba/smb.conf</filename> file, and add the following entries under the <emphasis role="italic">[sourcedocs]</emphasis> entry:

read list = @planning

write list = @authors, richard

Save the <filename>/etc/samba/smb.conf</filename> for the changes to take effect.