Red Hat Linux Networking

NFS disadvantages

NFS has its shortcomings, of course, primarily in terms of performance and security. As a distributed, network-based file system, NFS is sensitive to network congestion. Heavy network traffic slows down NFS performance. Similarly, heavy disk activity on the NFS server adversely affects NFS's performance. In both cases, NFS clients seem to be running slowly because disk reads and writes take longer. If an exported file system is not available when a client attempts to mount it, the client system...

Understanding the Red Hat Linux File System Structure

Linux Directory Structure

Understanding the organization, or layout, of the Red Hat Linux file system is one of the most important aspects of system administration. For administrators, programmers, users, and installed software, knowing how and where the files are stored on the system is critical for proper system operation. A standard should be in place that specifies locations for specific types of data. Fortunately, Red Hat has chosen to follow the standards outlined in the Filesystem Hierarchy Standard (FHS). This...

Customizing the kernel

Customizing the kernel involves two steps, choosing between building a modular or monolithic kernel, and then performing the actual kernel configuration. When configuring the kernel, you have two options for the device drivers needed to support various hardware devices in Linux Build device support directly into the kernel. You can build the drivers for all hardware on your system into the kernel. As you can imagine, the size of the kernel grows as device driver code is incorporated into the...

Key files commands and daemons

This subsection discusses the key files, commands, and daemons that make up an NFS server. On most Linux systems these files and programs include the following Configuration and status files NFS Server Configuration and Status Files NFS SERVER CONFIGURATION AND STATUS FILES The server configuration file is etc exports, which contains a list of file systems to export, the clients permitted to mount them, and the export options that apply to client mounts. Each line in etc exports has the...

Installing and building the source distribution

Installing and building Apache's source distribution enables you to select configuration defaults and compiled-in features that suit your needs, not someone else's. This section guides you through building Apache from scratch. To save download time, this chapter's source code directory includes the latest released version of the Apache Web server available at the time this book went to press. You might want to check Apache's home page (http httpd.apache.org ) for updates, patches, or even a...

Obtaining the latest kernel version

After you have determined the version of the kernel you are currently running, the next step is to obtain the latest version of the kernel source code. For simplicity's sake, the discussion assumes you want to use the stable kernel version. At any given time, there are almost always two versions of the Linux kernel available, the stable or production version and the unstable or development version. You can differentiate between the versions by looking at the kernel version numbers. The kernel...

Monitoring Network Traffic

Network bottlenecks are highly visible. Moreover, the nature of a network makes troubleshooting performance problems rather difficult because any number of failure or bottleneck points could exist. The culprit could be network cards, cabling, bridges, routers, gateways, or firewalls. Worse still, on a TCP IP Ethernet, everyone notices a network performance problem. Ethernet does not discriminate if the network is congested, everyone suffers equally. From the administrator's point of view,...

Configuring password authentication

The installation program displays the Authentication Configuration screen, shown in Figure 3-11, from which you can configure the password authentication options. You can enable or disable several options. Of these, the first two are already selected Enable MD5 passwords Select this option to enable users to use long passwords of up to 256 characters instead of the standard password that can be, at most, eight characters long. Note that MD5 refers to Message Digest 5, an algorithm developed by...

Setting Up a Network Interface Card NIC

Every Red Hat Linux distribution includes networking support and tools that can be used to configure your network. In this section you'll learn how to configure a computer for connection to an internal and external network. Even if the computer is not connected to outside networks, an internal network functionality is required for some applications. This address is known as the loopback and its IP address is 127.0.0.1. You should check that this network interface is working before configuring...

Maintaining the Server

WU-FTPD includes a number of commands for monitoring and administering the server, including ftpwho, ftpcount, ckconfig, xferstats, ftpshut, and ftprestart. ftpwho and ftpcount provide a snapshot of users currently logged in to the FTP server and how many users in each class, as defined using the class directive in etc ftpaccess, are logged in. Neither command accepts any options (except -V, which displays version information), so they are very simple to use. The output from ftpwho should...

How Web Servers Work

To understand Apache, its configuration, and how to fine-tune it for your own environment, you should understand how Web servers work in general. Otherwise, lacking this context, Apache's behavior and configuration might seem arbitrary. Figure 15-1 shows the general process that takes place when a Web browser requests a page and the Apache Web server responds. Figure 15-1 Apache transmits a document according to a client's request. Figure 15-1 Apache transmits a document according to a client's...

Formulating a security policy

What should your security policy consist of Well, a number of things Although the method brings grumbles from users, assigned, random passwords made up of a combination of numbers and capital and lowercase letters, all with no discernable meaning, are safest. (This procedure includes, most especially, the root account password.) Who has access to what Red Hat Linux allows you to create special groups and assign users to them. This means that some users might have access to devices such as CD...

Pattern Matching Operators

Before discussing the pattern matching operators, it will be helpful to define what pattern matching is. A pattern is a string that contains one of the wildcard characters discussed at the beginning of the chapter, *, , and . Pattern matching, then, refers to matching all or part of a variable's string value to such a pattern, and pattern matching operators are the Bash operators that perform these matches. Table 19-8 lists Bash's pattern matching operators. Table 19-8 BASH PATTERN MATCHING...

Using a Windows Printer from the Linux Computer

Since all distributions include a printer configuration tool, it is easiest to use this tool to help configure the printer. Red Hat Linux includes printtool, and this is what I use to configure the printer. Type printtool at a command prompt and after the program starts, click Add. Then choose SMB Windows95.NT printer and click OK (see Figure 9-26). Figure 9-26 Using the Red Hat printtool to configure a Samba printer Figure 9-26 Using the Red Hat printtool to configure a Samba printer It may be...

Configuring the Samba Client

From the Windows desktop click Start, then choose Settings Control Panel to open the Control Panel window as seen in Figure 9-14. Figure 9-14 The Windows Control Panel Figure 9-14 The Windows Control Panel Double click the Network icon and check for File and Printer Sharing for Microsoft Networks and Client for Microsoft Networks in the Configuration window showing installed network components. See Figure 9-15. Conjuration Identification Access Control The following network components ere...