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Red Hat Linux Bible: Fedora and Enterprise Edition

Christopher Negus

Graphical Administrative Interfaces

To help you simplify Linux administration, several graphical administrative utilities are now available. These interfaces attempt to organize the information that you need to get a whole job done in one place. The interface handles placing the information that you enter into the correct configuration files and setting up the correct commands to run.

Graphical interfaces are a step in the right direction toward making Linux useable by the general population. The problem is, however, that these don’t yet enable you to do everything that you need to do, so you often find yourself needing to edit a configuration file by hand after you enter the information into that file using a graphical application. You will find that you need to do this less for simple tasks (such as adding a user account) than you will for more complex tasks (such as configuring a network).

Another downside of graphical administrative interfaces in Linux is that they tend to cause versions of Linux to diverge. The configuration files created as you set up a dial-out Internet connection by using PPP with the Network configuration in Red Hat Linux, for example, are different from the files that you would create setting up PPP on a different version of Linux. This can make to getting information on your particular situation a bit difficult.

The following sections describe the major graphical interfaces used for administration in Red Hat Linux.

Using linuxconf

The most complete graphical utility for working with Red Hat Linux is linuxconf. As a GUI interface, linuxconf isn’t fancy. Don’t expect to see lots of icons or to drag and drop items on the display. It does, however, offer several significant advantages over just editing configuration files directly:

  • Configuration and control tools for many different features are all contained in one place. Just click an activity in the left column and a form for configuring the item appears in the right column. You don’t need to search blindly in etc for the right files to edit.
  • Some error checking is done. In many cases, linuxconf prevents you from entering invalid values in the fields.
  • Options are offered. If, for example, you are adding a network interface, you can click a menu to select from the interfaces that Linux knows about (such as PPP or Ethernet).

Administrative activities are divided into three major categories in linuxconf: Config, Control, and Status. Config activities enable you to set up your network interfaces (for both client and server features), work with user accounts, configure file systems, and manage how Linux boots. Control activities enable you to work with features that are already configured, including starting and stopping services, mounting/unmounting file systems, and controlling the files and systems used by linuxconf. Status activities enable you to view system logs.

Starting linuxconf

You can start linuxconf from a terminal window (linuxconf &). Figure 1 shows the Linuxconf window.

Figure 1: Linuxconf centralizes Linux administration in one graphical window.

TIP: Linixconf can also be operated from Netscape or another Web browser from any computer that can reach your system from the network. To do that, the remote computer would simply request port number 98 from your computer. If your computer were named comp1, for example, you could start linuxconf by typing the Web address: http://comp1:98/. (You may need to activate the linuxconf service for this to work.)

To choose a task to perform in linuxconf, click the task in the left column. A form representing the task appears on the right. Select the options that you want and fill in the necessary information. Accept the changes by clicking Accept or OK. Click Cancel after you are done. You can also use the following function keys and control keys with linuxconf:

  • Ctrl+X — If the current field contains a pop-up selection list (indicated by a down arrow), this key opens the list.
  • F3 — Escapes from any dialog box.
  • Ctrl+A — Goes to the beginning of the line.
  • Ctrl+B — Goes up one page.
  • Ctrl+D — Deletes the current character.
  • Ctrl+E — Goes to the end of the line.
  • Ctrl+F — Goes down one page.
  • Ctrl+K — Deletes text to the end of the line.

Linuxconf configuration tasks

Under the configuration section in linuxconf are tasks for setting up your network, creating user accounts, working with file systems, initializing system services, and choosing boot modes. Networking tasks are divided into those that apply to your computer as a client and those that apply to it as a server.

Linuxconf networking tasks

Client networking tasks enable you to view and configure information associated with your computer’s host name, the network interfaces that are attached to your computer, and the routes that you can use to get to other hosts and networks. Click the plus sign (+) next to Client tasks and select Basic host information. From the window that appears, here are some of the items that you can change:

  • Host name — Your host name is how other computers on the network identify yours. It can contain the full hostname.domainname form.
  • Adaptor — The network interfaces (that is, Ethernet cards, PPP dial-up connections, and so on) that give you access to the network can be viewed by clicking the Adaptor tabs on the Basic host information form. The information that you would need to enter in this form is described in detail in Chapter 15, "Setting Up a Local Area Network."

Your system resolves Internet host names into IP addresses by identifying DNS servers that can perform name-to-address resolution. Click the Name Server Specification (DNS) task to add your default domain and one or more name servers. You can also indicate in which domains to search for addresses.

Under Routing and Gateways, you can define how your networking requests are routed across gateway machines (those that are connected to your subnetwork and another subnetwork) to reach beyond your local network. You can also specify routes to other local area networks.

Other network services that you can configure include the Network Information Service (NIS), IPX interface, and serial IP connections (PPP, SLIP, and PLIP). NIS is a way of having a central server store the information that each client computer needs to start up. IPX is a networking interface protocol that is popular with NetWare servers, and PPP, SLIP, and PLIP are ways to connect by using Internet protocols across modems, direct connections, and other serial lines.

If you make any changes to your network configuration, you can activate those changes by clicking the Act/Changes button. You can either preview what needs to be done to activate the changes or click Activate the Changes for the changes to be implemented and the network to be restarted.

Under Server tasks, you can share your file systems with other computers on the network (by using NFS) and set up IP aliases for virtual hosts. You also find tasks for configuring a mail server and an Apache Web Server.

Other Linuxconf configuration tasks

Besides networking tasks, you can select from several other basic system tasks in linuxconf. Under User Accounts, you can add normal user accounts, special user accounts, e-mail aliases, and policies regarding user accounts. Under File Systems, you can add definitions of mountable local drives or NFS file systems (from remote systems) that can later be added to or removed from your system (by using mount and unmount tasks described in the Control section). Finally, you can add parameters that affect how your Linux system boots.

Linuxconf control tasks

The Control section of linuxconf enables you to work with Linux features that change the on-going operation of your Red Hat Linux system. Here are some of the tasks that you can do from this section:

  • Activate configuration — For changes that you make to take effect, some services must be stopped and restarted. This task checks what needs to be restarted, based on the changes that you have made, and then restarts those services after you say that you are ready.
  • Shutdown/reboot — Use this task to either shut down and halt your computer or reboot it.
  • Control service activity — You can enable or disable a variety of network services by selecting this task.
  • Mount/Unmount file systems — Any local or NFS file systems that you configured to be mountable (in the Configuration section) can be mounted or unmounted by using these tasks.
  • Configure superuser schedule — You can add commands that are run at a set schedule (by using the cron facility) as the root user by adding entries under this task.
  • Archive configurations — With this task, you can archive the configuration files that you have set up so that you can recall these saved configuration files later. This task can be used to get you back to a sane state if your configuration files get wrecked.
  • Switch system profile — You can recall a past archive of configuration files (and save the current configuration files) by using this task.
  • Control files and systems — Select tasks from this section to change the way that configuration files, commands, file permissions, modules, system profiles, and linuxconf add-ons are configured and used in linuxconf.
  • Date & time— Change the date, time, and time zone from this task.
  • Features — Modify the keyboard mapping used for your Linux computer, the language, or several features associated with how HTML is used on your computer.

After you have made changes to any configurations that require programs to be restarted, you can click Act/Changes. Then click the Activate the Changes button that appears. If errors are reported, click Yes to view those messages. Then you can view the log that was created from the changes.

Linuxconf subsection commands

Instead of using linuxconf, you can use commands to go directly to particular configuration sections. commands:

  • Filesystem configurator— Configures the file systems that your computer can access. This can include local drives and NFS volumes (mounted from remote computers). It also enables you to configure swap files and partitions and set the quota Filesystem configurator window (see Figure 2).

  • Figure 2: Mount local and remote file systems by using the Filesystem configurator.

  • Network configurator (netconf) — Configures your TCP/IP network. It enables you to add everything that you need to create connections to modems and Ethernet LANs. You can set up the Domain Name System (DNS), routing and gateways, and serial communications (PPP, SLIP, or PLIP). Figure 3 shows the Network configurator window.

  • Figure 3: Set up TCP/IP network connections by using the Network configurator.

  • User Account configurator (userconf) — Manages your computer’s user accounts. It enables you to add regular user and group definitions and then assign passwords to users. You can also add special user accounts, such as those that enable you to automatically log in and start a PPP, SLIP, UUCP, or POP connection. Figure 4 shows the User account configurator window.

  • Figure 4: Add regular and special user accounts in the User account configurator window.


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