2 System Administration Tools and Methods

2.1 Scripts and Files

Most of the tasks described in this book can be accomplished by using a combination of individual shell commands, using scripts and utilities, and by editing system files. This chapter describes:

Administration tools available from the Common Desktop Environment (CDE) graphical user interface. Use of this interface requires a graphics (windowing) terminal or workstation, and the installation of the CDE software subsets.
Remote system administration, using a modem connected to the console of the remote system

2.2 CDE Graphical User Interface

CDE is the 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.

2.2.1 CDE Administration Tools

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

Installation Applications
You can use these applications to set up installations, preconfigure some software subsystems, and access the UNIX shell.
Configuration Applications
After a system has been installed, you can use these applications to perform:
- Network Configuration with netconfig
- BIND Configuration with bindconfig
- NFS Configuration with nfsconfig
- Mail Configuration with mailconfig
- Print Configuration with printconfig
- Disk Configuration with diskconfig
Daily Administration Applications
After a system has been configured, you can use these applications to perform routine administrative tasks:
- Account Manager with dxaccounts
- Archiver with dxarchiver
- File Share with dxfileshare
- Host Manager with dxhosts
- License Manager with dxlicenses
- Shutdown Manager with dxshutdown
- System Information with dxsysinfo
Monitoring and Tuning Applications
While a system is running, you can use these applications to monitor and tune its resources:
- Kernel Tuner with dxkerneltuner
- Process Tuner with dxproctuner
Display Window Help Application
You can use the dxdw application to access the CDE commands from the graphical user interface.

2.2.2 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 Digital 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.

Network Configuration

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

Network Configuration
BIND Configuration
NFS Configuration
Printer Configuration

The menu interface for Mail Configuration is called mailsetup.

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

2.3.1.2 Setting the Configurable DCD Timer Value

The Digital 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.

2.3.1.3 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:

COM1_MODEM: ON or OFF
COM1_FLOW: NONE, HARDWARE, SOFTWARE, BOTH
COM1_BAUD: Consult your system hardware documentation.

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.

2.3.1.4 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.

2.3.2 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.

2.3.2.1 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 Digital UNIX features may be useful for remote administration:

The UNIX-to-UNIX system copy utility, uucp for copying scripts and files to the remote system. See the uucp(1) reference page for more information.
A kernel debugging tool, ikdebug can be invoked and used remotely. See the ikdebug((8)) reference page for more information. You may need to change an entry in the /etc/remote file to correct the baud rate. For example you may need to change the baud rate from 9600 baud in the following lines:
```
# access line for kernel debugger
kdebug:dv=/dev/tty00:br#9600:pa=none:
```
See the Kernel Debugging manual for additional information.

2.3.2.1.1 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.

2.3.2.1.2 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.

2.3.2.1.3 Ending a Remote Session

To end a remote session from the Digital 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.

2.3.3 Troubleshooting

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

The local modem does not dial out.
Check the cables and connections and ensure that the telephone lines are plugged into the correct sockets, and that you have a dial tone.
The remote modem fails to answer.
Ensure that the remote modem is set to auto-answer, ATS0=n, where n is the number of rings before the modem answers.
Review the modem(7) reference page and verify the settings for dial-in access.
The remote modem answers and then disconnects.
This is most likely to be due to incorrect settings for dial-in access. Review the modem(7) reference page and verify the settings for dial-in access.
The remote modem answers but only random characters are printed.
This problem is usually caused by a mismatch between the baud rate of the COMM port and that of the modem. Review the modem(7) reference page and verify the settings for dial-in access.
The connection is dropped when the remote system is shut down via the shutdown command.
The stty attribute hupcl is at the default setting. To prevent the line from disconnecting during a shut down, use the following command:
```
# stty -hupcl
```