2    System Administration Tools and Methods

This chapter explains the various tool options and administration methods available to you. Choices may be limited by the hardware, or by a particular task that you are performing. For example, you cannot use the graphical tools if you only have a character-cell terminal, or if the system is at the single-user prompt in standalone mode. Under these circumstances, you are limited to the command-line and to scripts that have character-cell interfaces.

Most administrative tasks can be accomplished using individual commands, by running a character-cell script, or by running a graphical interface under X windows. However, not all tools may offer all three types of interface, and there may be slight differences in the options offered by each interface. For example, a command may have a large number of options (flags) when used from the command line, but not all these options are presented in the graphical interface.

Avoid making manual edits to files. Experienced administrators may want to avoid using an interface or script, but this can often lead to changes to the format of the file. While these errors might not cause problems when running the system, they may cause problems during future update installations, when new information is automatically merged into the existing files. If you do make changes to individual system files, always use a command line utility such as rcmgr or sysconfig. If you need to correct a problem with a file by editing the file in single-user mode (using ed or vi) ensure that you preserve the format of the file. Section 4 reference pages document the correct formats of the various system files.

This chapter describes:

2.1    CDE Graphical User Interface

CDE is the preferred operating system interface and the SysMan graphical user interface becomes the preferred system administration tool on systems that can display the CDE. A command line interface to these tools is included for users of systems that have only character-cell displays or for users who prefer to use a command line interface to the CDE in a terminal window.

Documentation on using the tools is provided in the form of on-line help, and context-sensitive messages. The SysMan interfaces are not documented in this book However, you will find information relating to administrative tasks, and instructions for using alternative methods.

2.1.1    CDE Administration Tools

The following SysMan tools are available from the CDE control panel:

2.1.2    Accessing the SysMan Tools

The SysMan applications are also available in the DECwindows Motif and base X Windows graphical environments. In CDE, the SysMan applications are available in the Application Manager. You can access the Application Manager from the CDE Front Panel by clicking on its icon. The SysMan applications are organized into five groups within the System_Admin group. Double click on the System_Admin group to access the SysMan Configuration Checklist, the Welcome to SysMan online help volume, and the five application groups.

Online help is available for the SysMan applications without running the applications. Click on the Help Manager icon on the CDE front panel to display the online help browser. The browser includes help families for CDE, the CDE Desktop, and Tru64 UNIX System Management.

In DECwindows, the SysMan applications are listed in the Session Manager's Options menu. You can use the Applications Definitions menu item to add frequently used SysMan applications to the Applications menu. You can also customize your CDE workspace with the Create Action utility in the Desktop_Apps folder. Customized icons enable you to start SysMan applications directly from the workspace.

In other X Windows environments, the SysMan applications can be invoked from the command line. See the sysman_intro(8X) reference page for a list of the SysMan applications. This reference page also describes how to display the online help browser in graphical environments other than CDE.

To support nongraphical (terminal) environments, some SysMan applications offer command line and question and answer interfaces. The following applications have a command line interface. A single command starts the application, which then performs the actions specified by the command-line arguments.

The following applications have a question and answer interface invoked using the command-line argument -ui menu. The application prompts you interactively.

The menu interface for Mail Configuration is called mailsetup.

2.2    Remote System Administration

You can manage remote systems through a modem connection. A serial line console enables you to connect a local terminal to the remote system console through modems attached to your local system and to the communications port COMM1 of the remote system. The local system can be any terminal or terminal emulation device that enables a modem connection such as a dumb terminal, an X terminal window, or a personal computer (PC). To perform administrative tasks, you must be able to log in as root (or an account with administration privileges).

This connection is referred to as the console port. The terminal connection supports a limited set of communication rates up to 57,600, depending on the console firmware supported by your processor. Currently, this feature is only available on systems that support modems as console devices, such as the AlphaServer 1000A. Consult your system hardware documentation to find out if your system has such capabilities.

The console port enables you to do the following:

Note that running the Environment Configuration Utility (ECU) on the remote system will cause the modem to disconnect. For this reason, you should use the ECU to complete any environment configuration before setting up and using a modem as a console device.

2.2.1    Setting Up a Console Port

The following sections provide an overview of the steps required to set up a serial line console port and set up the remote modem for dial-in. It is assumed that your local (dial-out) modem is already installed and configured for use.

2.2.1.1    Connecting the Modem to COMM1

The CONSOLE environment variable on the remote system should be set to serial.

Refer the hardware documents supplied with your modem for connecting the modem to your system. Consult the modem(7) reference page to obtain the correct modem settings and for instructions on how to create the appropriate system file entries. In particular, the cons entry in /etc/inittab file should be modified so that the getty or uugetty process sets up the COMM port correctly. This line is similar to the following example: 


cons:1234:respawn:/usr/sbin/getty console console vt100

This line should be changes as follows if you are using a modem set to run at a baud rate of 38,400 as a console device: 


cons:1234:respawn:/usr/sbin/getty console M38400 vt100

2.2.1.2    Setting the Configurable DCD Timer Value

The Tru64 UNIX serial driver has been modified to allow the Carrier Detect (DCD) timeout value to be configurable. The default value for this timer is 2 seconds, which is in accordance with the DEC STD-052 standard and is acceptable for most modems. This timer is used to determine how long the driver must wait when the DCD signal drops, before declaring the line disconnected and dropping the DTR and RTS signals. Some modems expect DTR to drop in a shorter time interval, so refer to your modem documentation to verify the interval.

The timer can be modified via the /etc/sysconfigtab file or the sysconfig command to set the timer to 0 (no timeout period), 1, or 2 seconds. To set the timer via /etc/sysconfigtab, edit the file and include the following: 

ace:      
  dcd_timer=n

Where n = 0, 1, or 2

The syntax for modifying the timer via the sysconfig command is as follows: 

# sysconfig -r ace dcd_timer=n

Where n = 0, 1, or 2

Note that by modifying the value with the sysconfig command, the setting is lost when the system is rebooted. To preserve the setting across reboots, edit the /etc/sysconfigtab file.

2.2.1.3    Setting the Console Environment Variables

The COM1_MODEM, COM1_FLOW, and COM1_BAUD console environment variable settings must be equivalent to the getty or uugetty settings used when you created your system file entries for the modem.

Consult your hardware documentation for information on how to set the console environment variables. Typically, the variables are set when the system is shut down and in console mode, as shown in the following example: 

>>> set COM1_MODEM ON
>>> set COM1_FLOW SOFTWARE
>>> set COM1_BAUD 9600

Valid settings are as follows:

Note that if you change the baud rate, flow control, or modem setting (for example, using the getty command), the change will be propagated down to the console level and the environment variables will change automatically.

2.2.1.4    Verifying the Modem Setup

Dial the remote system and obtain a log-in prompt or console prompt, if the system is not booted. Log out or disconnect and ensure that the line hangs up correctly. Dial in again to ensure that you can reconnect.

2.2.2    Initiating a Console Port Connection

You can initiate a connection between the local and remote systems by different methods. A tip, kermit, or cu connection can be initiated from a terminal or X-terminal window or you can use a PC-based terminal emulator.

For example, use the tip command as follows: 


# tip [telephone number]
# tip cons

Where telephone_number is the telephone number of the remote system, including any prefixes for outside lines and long-distance codes. The second line is an example of an entry in the /etc/remote file, which you can use to specify details of remote systems and tip settings.

Once you have initiated the dial-out command, and the two modems have established a connection, the word connect is displayed on your local terminal window. Press the [Return] key and the console prompt (>>>) or the login: prompt will be displayed.

See the tip(1) reference page for more information.

2.2.2.1    Using the Console Port

Once you have access to the system and are logged in to a privileged account, you can perform any of the administration tasks described in this volume that do not require access to a graphical user interface, such as using commands and running utilities. Note that the following Tru64 UNIX features may be useful for remote administration:

2.2.2.1.1    Turning Off Console Log Messages

The syslogd daemon now has an internal switch to disable and enable messages to the console. This feature is invoked by the -s flag on the syslogd command line, or by running the following command: 


# /usr/sbin/syslog

See the syslog(1) reference page.

2.2.2.1.2    Shutting Down the Remote System

When you shut down the remote system, the modem connection will be dropped. To avoid this, use the following command before you shut down the system: 

# stty -hupcl

See the stty(1) reference page for more information.

When the shutdown is complete, you will still have access to the console prompt.

2.2.2.1.3    Ending a Remote Session

To end a remote session from the Tru64 UNIX operating system shell prompt, type Ctrl-D to log out and terminate the remote session. Otherwise, type +++ to put the modem into local command level, and type ATH followed by the Return key to hang up the connection.

2.2.3    Troubleshooting

If you have problems setting up your systems and connecting, check the set up as follows::