Using Samba, Second Edition

Chapter 1. Learning the Samba

Samba is an extremely useful networking tool for anyone who has both Windows and Unix systems on his network. Running on a Unix system, it allows Windows to share files and printers on the Unix host, and it also allows Unix users to access resources shared by Windows systems.

Although it might seem natural to use a Windows server to serve files and printers to a network containing Windows clients, there are good reasons for preferring a Samba server for this duty. Samba is reliable software that runs on reliable Unix operating systems, resulting in fewer problems and a low cost of maintenance. Samba also offers better performance under heavy loads, outperforming Windows 2000 Server by a factor of 2 to 1 on identical PC hardware, according to published third-party benchmarks. When common, inexpensive PC hardware fails to meet the demands of a huge client load, the Samba server can easily be moved to a proprietary “big iron” Unix mainframe, which can outperform Windows running on a PC many times. If all that weren’t enough, Samba has a very nice cost advantage: it’s free. Not only is the software itself freely available, but also no client licenses are required, and it runs on high-quality, free operating systems such as Linux and FreeBSD.

After reading the previous paragraph, you might come to the conclusion that Samba is commonly used by large organizations with thousands of users on their networks—and you’d be right! But Samba’s user base includes organizations all over the planet, of all types and sizes: from international corporations, to medium and small businesses, to individuals who run Samba on their Linux laptops. In the last case, a tool such as VMware is used to run Windows on the same computer, with Samba enabling the two operating systems to share files.

The types of users vary even more—Samba is used by corporations, banks and other financial institutions, government and military organizations, schools, public libraries, art galleries, families, and even authors! This book was developed on a Linux system running VMware and Windows 2000, with Adobe FrameMaker running on Windows and the document files served by Samba from the Linux filesystem.

Does all this whet your technological appetite? If so, we encourage you to keep reading, learn about Samba, and follow our examples to set up a Samba server of your own. In this and upcoming chapters, we will tell you exactly how to get started.

What Is Samba?

Samba is a suite of Unix applications that speak the Server Message Block (SMB) protocol. Microsoft Windows operating systems and the OS/2 operating system use SMB to perform client-server networking for file and printer sharing and associated operations. By supporting this protocol, Samba enables computers running Unix to get in on the action, communicating with the same networking protocol as Microsoft Windows and appearing as another Windows system on the network from the perspective of a Windows client. A Samba server offers the following services:

• Share one or more directory trees

• Share one or more Distributed filesystem (Dfs) trees

• Share printers installed on the server among Windows clients on the network

• Assist clients with network browsing

• Authenticate clients logging onto a Windows domain

• Provide or assist with Windows Internet Name Service (WINS) name-server resolution

The Samba suite also includes client tools that allow users on a Unix system to access folders and printers that Windows systems and Samba servers offer on the network.

Samba is the brainchild of Andrew Tridgell, who currently heads the Samba development team. Andrew started the project in 1991, while working with a Digital Equipment Corporation (DEC) software suite called Pathworks, created for connecting DEC VAX computers to computers made by other companies. Without knowing the significance of what he was doing, Andrew created a file-server program for an odd protocol that was part of Pathworks. That protocol later turned out to be SMB. A few years later, he expanded upon his custom-made SMB server and began distributing it as a product on the Internet under the name “SMB Server.” However, Andrew couldn’t keep that name—it already belonged to another company’s product—so he tried the following Unix renaming approach:

$ grep -i '^s.*m.*b' /usr/dict/words

And the response was:

salmonberry
samba
sawtimber
scramble

Thus, the name “Samba” was born.

Today, the Samba suite revolves around a pair of Unix daemons that provide shared resources—called shares or services—to SMB clients on the network. These are:

smbd

A daemon that handles file and printer sharing and provides authentication and authorization for SMB clients.

nmbd

A daemon that supports NetBIOS Name Service and WINS, which is Microsoft’s implementation of a NetBIOS Name Server (NBNS). It also assists with network browsing.

Samba is currently maintained and extended by a group of volunteers under the active supervision of Andrew Tridgell. Like the Linux operating system, Samba is distributed as open source software (http://opensource.org) by its authors and is distributed under the GNU General Public License (GPL). Since its inception, development of Samba has been sponsored in part by the Australian National University, where Andrew Tridgell earned his Ph.D. Since then, many other organizations have sponsored Samba developers, including LinuxCare, VA Linux Systems, Hewlett-Packard, and IBM. It is a true testament to Samba that both commercial and noncommercial entities are prepared to spend money to support an open source effort.

Microsoft has also contributed by offering its definition of the SMB protocol to the Internet Engineering Task Force (IETF) in 1996 as the Common Internet File System (CIFS). Although we prefer to use the term “SMB” in this book, you will also often find the protocol being referred to as “CIFS.” This is especially true on Microsoft’s web site.