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3.Try to telnet to the local host. telnet localhost

If the local host doesn’t respond, telnet service is disabled.

4.Edit the /etc/inetd.conf file to uncomment the telnet line by removing the pound sign.

After you finish, restart the inetd process: killall -HUP inetd

5.Use telnet again to connect to your own machine: telnet localhost

You should now get a connection.

Answers to Chapter Questions

Chapter Pre-test

1.The most common hardware problems that cause a tape backup to fail include bad tapes, neglecting to periodically clean tape heads, and failed drive mechanisms.

2.The ping command sends a network packet to a host. If the host replies with an acknowledgment, then you know that it has received the request. If a reply is not received, a problem has occurred between the two hosts.

3.Many programs use the same libraries, or two different versions of the same library. If the library is updated, it may cause the other program to stop functioning.

4.The lpr command can be used to send a job to the printer.

5.The destination e-mail server should respond with a reply, sometimes called a “bounced” message letting you know that the e-mail did not reach its destination.

6.The traceroute command is used to identify the number of router hops from one host to another host. It is helpful in identifying the source of network communication problems.

7.The command to show your current running processes is ps.

8.If an unauthorized person is trying to break into someone’s account, the system will lock out login attempts after a certain number of failures. This decreases the chance of an intruder breaking into an account by attempting multiple passwords.

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9.The logs of the application should be examined to narrow down the source of the failure.

10.You can try using telnet on your own host to ensure that the telnet services are working.

Assessment Questions

1.B. Because the same errors occurred using different tapes, the error probably originated from the drive, and most likely the tape heads need cleaning. For review, see the “Backup and Restore Errors” section.

2.D. The user’s account is set to lock after too many failed logins. This helps stop an unauthorized user from breaking into an account. For review, see the “Login problems” section.

3.B. The user does not have permissions for the directory. If the user should not be seeing the data, then this error is normal because they are trying to access files that they are unauthorized to see. For review, see the “File and directory permissions” section.

4.A. The lpq command can be used to see the status of a print queue. For review, see the “Printing problems” section.

5.C. To trace the network connection to locate where the break in communications exists, use the traceroute command. For review, see the “Networking connectivity” section.

6.C. Many software packages are dependent on other programs to function properly. If these dependencies do not exist, you must install them before installing your software package. For review, see the “Software Package Problems” section.

7.D. Set expiration dates for employees who may only be contracted for a certain amount of time. When their contracts expire, their account will automatically be locked. For review, see the “Login problems” section.

8.A. When an application fails, the first thing that you should do to help troubleshoot the problem is to examine the application logs for the particular error that caused the application to fail. For review, see the “Application Failures” section.

9.C. Because the print jobs have made it to the queue, the most likely problem is that the printer is turned off, or is offline. For review, see the “Printing problems” section.

10.B. If the user is trying to connect using the pop3 protocol, the proper port to use is 110 because port 143 is for the imap protocol. For review, see the “Application Failures” section.

11.D. If the telnet service is commented out from the /etc/inetd.conf file, it will disable connections on that protocol. For review, see the “Application Failures” section.

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12.A. Some organizations choose to implement time restrictions on accounts, so in high security environments, no one is able to log in during certain time periods. For review, see the “Login problems” section.

13.C. The best command to use for testing network communications is the ping command. The ping command sends a network packet to the remote server, and if it is on the network, will send a reply back. For review, see the “Networking connectivity” section.

14.B. The lpr command is used to send a file to a printer. lpq and lprm are commands used for examining and manipulating the print queue. For review, see the “Printing problems” section.

15.B. Typically, shared directory permissions are issued by using groups rather than by assigning them on an individual basis. For review, see the “File and directory permissions” section.

16.A. If a problem occurs with the login process, and no responses are received from the server, most likely you have a networking problem or a problem with the server. For review, see the “Login problems” section.

17.D. If the e-mail was returned, all mail services are working properly, but the destination e-mail address was wrong. For review, see the “Application Failures” section.

18.C. If the print job makes it to the destination print queue, you most likely have a problem with the printer, as this is the last destination for the print job. For review, see the “Printing problems” section.

19.B. The retention setting on your backup tapes tells your system how long to keep data on a tape before allowing it to be overwritten and recycled. If the time is set for too long, it won’t write over the older data, causing the tape to quickly fill up. For review, see the “Backup and Restore Errors” section.

20.C. You should always check the logs of a failed application because they will give you more detailed error messages to help you troubleshoot the problem. For review, see the “Application Failures” section.

Scenarios

1.To initially test network communications, use the ping command, which will immediately tell you if the server is alive on the network or not:

ping 10.1.2.100

If your ping request times out, and you haven’t received a reply, move on to using the traceroute command to find where the network communication breakdown is occurring:

traceroute 10.1.2.100

The traceroute command sends out network packets to find out at which point on the chain of routers the communication stops.

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2.To troubleshoot a problem like this, start with the most obvious things:

•Is the printer on?

•Is the printer online?

•Is the printer out of paper?

After you have gone through the basic questions, examine how the client is trying to print the file:

•Is the user printing from an X application?

•Can the user print from another X application?

•Can the user print from the command line?

If you find that the user can successfully print from other applications or the command line, then the problem may be the printing configuration of that particular program.

If this does not solve your problem, check the server print queues to see if any problems occurred there:

lpq -P[printername]

The administrator can use this command to check the status of any print queue. From this point, you can tell whether the user’s print job actually made it to the queue, and is awaiting to be printed.

You may need to ensure that the lpd daemon is running so that it can service jobs in the print queue and send it to the appropriate printer:

ps -ef | grep lpd

If the daemon is not running, you need to start it again.

Continued

EXAM OBJECTIVES (CONTINUED)

7.7 Remove and replace hardware and accessories (e.g., cables and components) based on symptoms of a problem by identifying common symptoms and problems associated with each component and how to troubleshoot and isolate problems

7.9 Identify proper procedures for diagnosing and troubleshooting ATA devices

7.10 Identify proper procedures for diagnosing and troubleshooting SCSI devices

7.11 Identify proper procedures for diagnosing and troubleshooting peripheral devices

7.12 Identify proper procedures for diagnosing and troubleshooting core system hardware

7.13 Identify and maintain mobile system hardware (e.g., PCMCIA, APM)

CHAPTER PRE-TEST

1.What is an IRQ?

2.What should be the SCSI ID of the host adapter?

3.What is APM?

4.When does a kernel need SMP support?

5.What do you use to configure an IDE hard drive as a master or slave?

6.What type of memory can perform error checking and correcting?

7.What is the function of the BIOS?

8.What support does the kernel require in order to run laptop devices?

9.Why does a SCSI bus need to be terminated?

10.What is USB?

Answers to these questions can be found at the end of the chapter.