Preface

Computer networks have changed our lives. They grew slowly, and mostly unnoticed, in the 1970s and 1980s. In the 1990s, though, something happened . Perhaps it was the availability of the World Wide Web (WWW, or Web) and graphical Web browsers, which made computer networks accessible to Grandma Dorothy and Uncle Stan. Maybe it was that the availability of network connections had reached a critical threshold. Perhaps the quality and quantity of network-enabled software passed a critical threshold. Possibly it was two or all three of these things, or something else entirely. In any event, networks became noticeable. Most importantly, the Internet became noticeable.

The Internet comprises millions of computers, many of which run servers ”software packages designed to listen for and respond to data transfer requests from other computers. Because the protocols upon which the Internet was built were designed to work in a cross-platform manner, both Internet clients and the servers they use run on many different platforms. One of the most popular of these is Linux. Coupled with inexpensive x 86 hardware, Linux makes a very cost-effective server platform for small and mid- sized sites. Indeed, with increasing computer performance and Linux versions working their way up the computer performance hierarchy, Linux is beginning to make inroads into the large server market. Thus, with Linux on everything from tiny network appliances to large servers, knowing how to set up and maintain a Linux server system is an important skill for networking professionals today.

Which servers, though? There are hundreds, if not thousands, of individual server programs. Most general-purpose Linux networking books focus on a handful of popular servers ”Web (HTTP) servers like Apache, login servers like Telnet and SSH, file servers like NFS and Samba, and a few others. These books present enough information to get a user up and running, but little more. They also give short shrift to servers that are less visible but that are often extremely important, like DHCP servers, time servers, and Kerberos. This book takes a different approach to Linux networking: I assume that you know at least a minimal amount about Linux and networking in general, and you want to take you skills to a higher level. Although this book does cover the "usual suspects ," it spends less time introducing the basics and more time describing advanced or unusual configurations. This book also covers some of the servers and topics that are neglected in most entry-level Linux networking books. The result is the closest thing possible to a book that's both a general Linux networking book and an advanced Linux networking book.

To be sure, you won't learn everything there is to know about complex packages like Apache or Samba in this book. The relevant chapters provide quick introductions to these tools, a summary of some popular techniques you won't find covered in other introductory Linux networking books, and pointers to additional resources. This book's approach is to be a general-purpose Linux networking book for people who are not novices.