Chapter 17: Network Administration

Although a computer running the UNIX System is quite useful by itself, it is only when it is connected with other systems that the full capabilities of the system are realized. Earlier chapters have described how to use the many communications and networking capabilities of UNIX. These network capabilities include programs for electronic mail such as sendmail as well as TCP/IP utilities for remote login, remote execution, terminal emulation, and file transfer. They also include NFS (Network File System) and the associated management structure, NIS (Network Information Services).

In this chapter, you will learn how to administer your system so that it can connect with other systems to take advantage of these networking capabilities. You will learn how to manage and maintain these connections and how to customize many network applications. Also, you will learn about facilities for providing security for networking, as well as potential security problems. The secure shell, which is a replacement for the Berkeley Remote Commands, is discussed in Chapter 9.

You will also learn about, and how to administer, the TCP/IP system, the sendmail mail application, DNS (Domain Name Service), and NFS (Network File System). We will discuss some network performance concepts and what tools exist to enhance performance or correct performance problems. Finally, we will briefly discuss web-based network issues, including routing, firewalls (and firewall security), and proxy servers.

Network Administration Concepts

You must understand many aspects of network administration to ensure that your network runs well, and that you can provide needed network services to your users. One aspect of network administration is the installation, operation, and management of TCP/IP networking. Before you can manage a network, you must install and set up the Internet utilities that provide TCP/IP networking services. You must also obtain an Internet address to identify your machine to other machines on your network. You need to find out how to configure your system to allow remote users to transfer files from your system using anonymous FTP. You also need to learn some tools for troubleshooting TCP/IP networking problems.

Administering the mail system is another important aspect of networking administration. You must learn how to administer the sendmail mail environment to customize the way your system sends and receives mail (use of e-mail systems is described in Chapter 8). You should also know how to use the Simple Mail Transfer Protocol (SMTP), part of the Internet Protocol Suite, to send mail. You need to learn how to control to whom mail may be sent (Chapter 10 discusses sending and receiving mail over the Internet).

Installing, setting up, configuring, and maintaining distributed file systems is also an important part of UNIX network administration. You need to understand administering the distributed file systems supported by UNIX. You need to learn how to install and set up the Network File System (NFS) to manage common resources used by your entire network, as well as the Distributed File System (DFS) to manage select portions of it.

UUCP system administration is also a network administration topic. It is covered in depth on the companion web site, http://www.osborne.com/unixtcr/webcomp.htm.