Chapter 31
Troubleshooting the Network

It is wonderful when everything works as it should, but there is a finite life to everything. This means that no matter how well your network might be operating today, it is only a matter of time before there is a failure in cards, cabling, or any other component from which the network is built.

This chapter explores the following two components of network management:

Regardless of how well you do the first, an occasion will come when you will have to do the second. This chapter places primary emphasis on details that can easily become test fodder. Your purpose for reading this chapter is that you want to be able to answer questions on the Novell tests. Aside from that, the material is presented in as practical a manner as possible, and lends itself well to use in the real world.

Problem Prevention

Preventing problems after a network is up and running is one of the primary jobs of an administrator. Because there are so many different types of prob-lems that can occur, one cannot plan for all eventualities. The possibilities, however, can be divided into the following four categories:

The following sections examine each of these.
Physical Problems
Temperature is one of the most critical envi-ronmental components affecting a computer's operation--whether a server or a workstation. Ambient temperature figures in, but more importantly is the temperature inside the computer. There can be as much as a 40 degree difference between the inside and outside of a computer due to the heat generated by the components. One reason for leaving computers turned on all the time is to prevent the internal temperature from fluctuating too greatly.

When new equipment arrives, you should allow it to adjust to room temperature before using it. This assures that there will not be undue thermal strain on the components, should they have been bouncing around in a frozen FedEx truck for three days.

It is critical that a server have adequate ventilation to keep from overheating, otherwise "chip creep" can occur wherein integrated circuits lose their seating and contact with the socket. It is equally important that ambient air, which is sucked into the machine, be filtered and be of as high a quality as possible. A consistent temperature in the room should be maintained, and particles such as smoke and dust should be filtered out as much as possible with appropriate filtration devices.

Electrical Problems
Whereas physical problems can deteriorate a server or other computer slowly, electrical problems tend to do it immediately. They can destroy components, trash data, and make you wonder why you didn't keep the job at ChemLawn.

The four types of electrical problems are as follows:


Note: When discussing noise, there are two acronyms commonly used. Radio Frequency Interference (RFI) is caused by microwaves, ovens, and appliances. Electromagnetic Interference (EMI) is caused by lights, radar, and industrial tools.
Security
Network security, and the implementation thereof, is the responsibility of the system administrator. Electronic Data Processing (EDP) Environmental Security entails thoroughly thinking through all the risks in your installation and creating a plan for dealing with them.

The following are four types of threats:

  1. Destruction
  2. Corruption
  3. Disclosure
  4. Interruption
To deal with the possibility of these threats, the administrator should think about each network segment and evaluate what potential risks there are. Next, he should evaluate and implement steps to minimize those risks effectively.

Some examples of security that can be implemented include the following:

Encryption also can be used to keep an intruder from understanding data that he intercepts. Beginning with NetWare 3.11, encryption is now standard, providing the SET command has ALLOW UNENCRYPTED PASSWORDS set to OFF.

Viruses
In simple terms, viruses are programs that interfere with the normal flow of processing. Viruses interfere by changing files and configurations, or by attaching themselves to everything they come in contact with and growing exponentially.

Viruses, by nature, require some action to activate them, and so they attach themselves to executable files. Those files are usually denoted by their extension, which can be BAT, EXE, or COM. Overlays, OVL files, provide other opportunities, however, as do FAT tables and boot sectors.

Very rarely have there been occurrences of viruses shipping with retail software. Most of the time, viruses enter the workplace through pirated software, downloaded shareware, or other suspect software. In a perfect world, the best solution is to prevent anyone other than the system administrator from installing software on the network. In this sense, "network" refers to all things physically attached--not only the server, but all workstations, too.

Given that there is no perfect world, and that you often cannot prevent installation of software on an individual's workstation, you must contend with the possibility of a virus attack. To do so, you should perform the following:

Bear in mind that NetWare includes some safeguards against virus attacks. For one thing, the NetWare FAT table is different from that of workstations and cannot be attacked. Therefore, NetWare viruses are not as common as DOS viruses, and most virus attacks occur on workstations, as opposed to the server.

roubleshooting

After a problem has occurred, prevention is a meaningless word and troubleshooting comes into play. The overall goal of troubleshooting is to restore service in a timely manner. The following are the four steps to the basic troubleshooting model:
  1. Gather information.
  2. Develop an attack plan.
  3. Isolate the problem and execute the plan.
  4. Document what was done.
By following these four steps, you can successfully restore a network to its fully operational state in the most efficient time possible. The importance of the fourth step cannot be overstated; it is easy to see where an experienced administrator has an advantage over an inexperienced one.


Note: There are several questions you should ask when someone first reports a problem (and before you ever arrive on site). As rudimentary as these questions might seem, taking the time to ask them will save you an enormous amount of time in the long run.
The four step troubleshooting model discussed earlier suggests the following steps to solving workstation problems:

  1. Rule out any possibility of user error.
  2. Check the physical site to verify that all is as it should be. Make certain that an electrical cord or printer cable did not come unplugged.
  3. Power everything down and then back up.
  4. Back up data if there is a question of storage media (a hard drive or drives).
  5. Eliminate as much overhead as you can. If the problem is with a workstation, reduce the CONFIG.SYS and AUTOEXEC.BAT files to the bare minimum and try the process again. Be certain that all terminate-and-stay-resident (TSR) programs that do not need to boot to get on the network are commented out of the AUTOEXEC.BAT file.
Whether solving problems on a workstation or server, you should always think in terms of dollars. During the hypothesis stage, consider what all the possibilities are and try those that cost the least first. Keep in mind that dollars are associated not only with any components that might need replacement, but also with downtime and the time of the administrator.]
Documents and Records
As mentioned earlier, the importance of documentation cannot be overstated. The importance of good documentation can never be surpassed by any other tool. Even on the smallest of networks, time and money can be saved by documenting problems and keeping good records.

You should maintain three types of records--those relating to the LAN system, the history surrounding it, and the resources available.

For the LAN system, there should be a detailed map identifying the location of users, and all tangible components: printers, routers, bridges, and so forth. You also should keep an inventory of the components and documentation on cabling and the workstations.

The history of the LAN should include user profiles, what the purpose of the LAN is, a log of past problems, and usage information. Not only can this come in handy when an administrator is trying to diagnose a problem, but also when said administrator meets a bus somewhere other than the bus stop. Should a change in administrators take place, there is no better way to keep a business on its feet than to have its network thoroughly documented.

The documentation regarding available resources should include information about the protocols and routing in use, as well as the LAN architecture. The most important resource of all, however, is people. You should have a chart of people and phone numbers readily available for when problems become too difficult for the administrator. VAR numbers, manager numbers, and any other emergency personnel numbers should be kept in an easy to find location.

Diagnostic Software
Third-party, diagnostic software is used to provide information about hardware. That hardware can be virtually anything from the server to a workstation to a cable. A considerable number of packages are available at a variety of prices. The most important consideration should be that they offer information that is useful to you.

Check It PRO is one program that can give quick facts about your hardware and operating system. It can also benchmark the components and show information about the interrupts.

There are a variety of programs with similar features. The following shows an example of output generated at a workstation with System Information--one of the tools available in Norton Utilities:

         Computer Name: IBM AT
      Operating System: DOS 6.20
   Built-in BIOS dated: Friday, January 15, 1988
        Main Processor: Intel 80386              Serial Ports: 2
          Co-Processor: Intel 80387            Parallel Ports: 3
 Video Display Adapter: Video Graphics Array (VGA)
    Current Video Mode: Text, 80 x 25 Color
 Available Disk Drives: 13, A: - C:, F: - I:, P:, S:, V:, X: - Z:

DOS reports 639 K-bytes of memory:
   254 K-bytes used by DOS and resident programs
   385 K-bytes available for application programs
A search for active memory finds:
   640 K-bytes main memory     (at hex 0000-A000)
   128 K-bytes display memory  (at hex A000-C000)
   128 K-bytes extra memory    (at hex C000-E000)
 1,024 K-bytes expanded memory
ROM-BIOS Extensions are found at hex paragraphs: C000

  Computing Index (CI), relative to IBM/XT: Testing...   73.0
       Disk Index (DI), relative to IBM/XT: Not computed. No drive specified.

Performance Index (PI), relative to IBM/XT: Not computed. 
Much of the same workstation information can be achieved with newer versions of DOS and MSD utility. The following is an excerpt from a report run on the same machine with this utility:
       Microsoft Diagnostics version 2.01    1/24/95    7:44pm   Page  1
    ========================================================================

    ------------------------ Summary Information --------------------------

                  Computer: Gateway/Phoenix, 486DX
                    Memory: 640K, 15104K Ext, 1024K EMS, 1024K XMS
                     Video: VGA, ATI , Ultra
                   Network: Novell, Shell 4.10.00
                OS Version: MS-DOS Version 6.20, Windows 3.10
                     Mouse: Serial Mouse 7.05
            Other Adapters: Game Adapter
               Disk Drives: A: B: C: F: G: H: I: P:
                 LPT Ports: 3
                 COM Ports: 2

   ------------------------------ Computer ------------------------------

              Computer Name: Gateway
          BIOS Manufacturer: Phoenix
               BIOS Version: 680486 ROM BIOS PLUS Version 0.10 G21-2
              BIOS Category: Phoenix PC/AT Compatible BIOS
              BIOS ID Bytes: FC 81 00
                  BIOS Date: 01/15/88
                  Processor: 486DX
           Math Coprocessor: Internal
                   Keyboard: Enhanced
                   Bus Type: ISA/AT/Classic Bus
             DMA Controller: Yes
              Cascaded IRQ2: Yes
          BIOS Data Segment: None

    ------------------------------ Network ------------------------------

                           Network Detected: Yes
                               Network Name: Novell
                   MS-DOS Network Functions: Not Supported
                            NetBIOS Present: No
                              Shell Version: 4.10.00
                                   Shell OS: MS-DOS
                           Shell OS Version: V6.20
                              Hardware Type: IBM_PC
                             Station Number: 3
                    Physical Station Number: 0060:8C84:A8DD
                              IPX Installed: Yes
                              SPX Installed: Yes
                          ODI/LSL Installed: Yes
Regardless of which utility you use, you should run reports regularly and store them in a place where they are easily accessible. When problems arise, immediately run the utility again and look for any discrepancies that signal problems.

Questions

  1. To reduce problems with static electricity, ______.
    A. place a humidifier in the computer room
    B. use proper antistatic protection such as grounded hardware
    C. keep Styrofoam cups away from computers
    D. All of the Above

  2. Which of the following is not a type of electrical problem?
    A. Electro-Static Discharge
    B. Crosstalk
    C. Ephemeral
    D. Transients

  3. EMI includes all of the following except ______.
    A. appliances
    B. radar
    C. power tools
    D. ignition systems

  4. Noise is ______.
    A. low voltage, low current
    B. low voltage, high current
    C. high voltage, low current
    D. high voltage, high current

  5. Encrypted passwords ______.
    A. are the default with NetWare 3.1x
    B. can be turned on starting with NetWare 3.12
    C. can be implemented with Check It PRO
    D. couldn't keep my big brother out
Answers
  1. D
  2. C
  3. A
  4. A
  5. A



(255)