1. In which of the following modes of the CLI could you configure a description of EthernetO?
Answer: E. The description command is an interface subcommand.
2. In which of the following modes of the CLI could you issue a command to reboot the router?
Answer: B. The reload command is an exec command, so it cannot be issued from any configuration mode. User mode does not allow the use of the reload command.
3. What type of router memory is used to store the configuration used by the router when it is up and working?
Answer: A. The IOS loads the config from NVRAM into RAM during the boot sequence; therefore, the router uses the configuration in RAM for normal operations.
4. What type of router memory is used to store the operating system used for low-level debugging and not for normal operation?
Answer: B. The ROMMON operating system is stored in ROM.
5. What command copies the configuration from RAM into NVRAM?
Answer: F. The first parameter identifies the source of the config, and the last parameter identifies the destination.
What mode prompts the user for basic configuration information?
Which of the following could cause a router to change the IOS that is loaded when the router boots?
Answer: D and F. The boot command is a configuration command that identifies the source and possibly the name of the IOS to load. The configuration register tells the router the source from which to find the file containing the IOS.
Which of the following hexadecimal values in the last nibble of the configuration register would cause a router to not look in Flash memory?
Answer: A and B. A 0 makes the router load ROMMON code; a 1 makes the router load the RXBOOT IOS image.
Imagine that you have configured the enable secret command, followed by the enable password command, from the console. You log out of the router and log back in at the console. Which command defines the password that you had to type to access the router again from the console?
Answer: C. The password subcommand, under the line console 0 command, sets the console password.
Imagine that you have configured the enable secret command, followed by the enable password command, from the console. You log out of the router and log back in at the console. Which command defines the password that you had to type to access privileged mode?
Answer: B. If both are configured, the enable secret password is required to gain access to privileged mode.
What are the two names for the same CLI mode in a router, that when accessed, enables you to issue exec commands that could be disruptive to router operations?
Answer: Enable mode and privileged mode. Both names are commonly used and are found in Cisco documentation.
What are three methods of logging on to a router?
Answer: Console, auxiliary port, and Telnet. All three cause the user to enter user exec mode.
3. What is the name of the user interface mode of operation used in which you cannot issue disruptive commands?
Answer: User exec mode.
4. Can the auxiliary port be used for anything besides remote modem user access to a router? If so, what other purpose can it serve?
Answer: Yes. For direct attachment of a terminal, and dial for the purpose of routing packets. Although it originally was created to support remote administration access, many customers use an auxiliary port for dial backup, particularly when analog lines are desired or when that is all that is available.
5. What command would you use to receive command help if you knew that a show command option begins with a c but you cannot recall the option?
Answer: show c?. Help would appear immediately after you typed the ? symbol. You would not need to press Enter after the ?. If you did so, the router would try to execute the command with only the parameters that you had typed after the ?.
6. While you are logged in to a router, you issue the command copy ? and get a response of "Unknown command, computer name, or host." Offer an explanation for why this error message appears.
Answer: You were in user mode. You must be in enable/privileged mode to use the copy command. When in user mode, the router does not provide help for privileged commands, and it treats the request for help as if there is no such command.
7. Is the number of retrievable commands based on the number of characters in each command, or is it simply a number of commands, regardless of their size?
Answer: The number of commands. The length (that is, the number of characters) of each command does not affect the command history buffer.
8. How can you retrieve a previously used command? (Name two ways.)
Answer: Ctrl-p and up arrow (literally the up arrow key on the keyboard). Not all terminal emulators support Ctrl-p or the up arrow, so recalling both methods is useful.
9. After typing show ip route, which is the only command that you typed since logging in to the router, you now want to issue the show ip arp command. What steps would you take to execute this command by using command-recall keystrokes?
Answer: Press the up arrow, press Backspace five times, and type arp. The up arrow key retrieves the show ip route command. Backspace moves the cursor backward and erases the character. Typing inserts the characters into the line.
10. After typing show ip route 126.96.36.199, you now want to issue the command show ip route 188.8.131.52. What steps would you take to do so, using command-recall and command-editing keystrokes?
Answer: Press the up arrow or Ctrl-p, then press Ctrl-b (or the left arrow) twice, and press Backspace once; and type 4. The Ctrl-b and left arrow keys back up one character in the line, without deleting the character. The Backspace key deletes the 1, in this case. And newly typed characters appear where the cursor sits in the command line.
11. What configuration command causes the router to require a password from a user at the console? What configuration mode context must you be in? (That is, what command[s] must be typed before this command after entering configuration mode?) List the commands in the order in which they must be typed while in config mode.
line console 0 login
Answer: The line console 0 command is a context-setting command; it adds no information to the configuration. The command can be typed from any part of configuration mode. The login command, which follows the line console 0 command, tells IOS that a password prompt is desired at the console.
12. What configuration command is used to tell the router the password that is required at the console? What configuration mode context must you be in? (That is, what command[s] must you type before this command after entering configuration mode?) List the commands in the order in which they must be typed while in config mode.
line console 0 password xxxxxxx
Answer: The password command tells IOS the value that should be typed when a user wants access from the console. This value is requested by IOS because of the login command. The password xxxxxxx must be typed while in console configuration mode, which is reached by typing line console 0.
13. What are the primary purposes of Flash memory in a Cisco router?
Answer: To store IOS and microcode files. In most routers, only IOS is stored in flash. If microcode is upgraded, the files also reside in Flash memory.
14. What is the intended purpose of NVRAM memory in a Cisco router?
Answer: To store a single configuration file, used at router load time. NVRAM does not support multiple files.
15. What does the NV stand for in NVRAM?
Answer: Nonvolatile. NVRAM is battery powered if it is really RAM. In some routers, Cisco has (sneakily) used a small portion of Flash memory for the purpose of NVRAM, but Cisco would not ask such trivia on the test.
16. What is the intended purpose of RAM in a Cisco router?
Answer: RAM is used as IOS working memory (storing such things as routing tables or packets) and for IOS code storage. (In some router models, not all IOS is copied into RAM. Some of IOS is left in Flash memory so that more RAM is available for working memory.) It also holds the currently-in-use configuration file called running-config.
17. What is the main purpose of ROM in a Cisco router?
Answer: To store a small, limited-function version of IOS and to store bootstrap code. Typically, this type of IOS is used only during maintenance or emergencies.
18. What configuration command would be needed to cause a router to use an IOS image named c2500-j-l.112-14.bin on TFTP server 184.108.40.206 when the router is reloaded? If you forgot the first parameter of this command, what steps must you take to learn the correct parameters and add the command to the configuration? (Assume that you are not logged in to the router when you start.)
boot system tftp c2500-j-l.112-14.bin 220.127.116.11
Answer: As for the second part of the question: Log in from con/aux/telnet, type the enable command, type the enable password, type the configure terminal command, and type boot ?. Help appears for the first parameter of the boot command.
19. What command sets the password that would be required after typing the enable command? Is that password encrypted by default?
Answer: enable password or enable secret. The password in the enable command is not encrypted, by default. The enable secret password is encrypted using MD5.
20. To have the correct syntax, what must you add to the following configuration command?
banner This is Ivan Denisovich's Gorno Router--Do Not Use
Answer: This command does not use a delimiter character at the beginning and end of the text. The correct syntax follows:
Answer: As typed, IOS would think that the letter T was the delimiter character, so the banner actually would be "his is Ivan Denisovich's Gorno Rou". The motd parameter is not shown because it is not required. An alternate correct command would be this: banner motd # This is Ivan Do Not Use #
21. Name two commands that affect the text used as the command prompt. Answer: hostname and prompt.
22. When using setup mode, you are prompted at the end of the process for whether you want to use the configuration parameters that you just typed in. Which type of memory is this configuration stored in if you type yes?
Answer: Both NVRAM and RAM. Setup is the only IOS feature that modifies both the active and the startup configuration files as the result of one action by the user.
23. What two methods could a router administrator use to cause a router to load IOS stored in ROM?
Answer: Setting the configuration register boot field to binary 0001, or adding boot system rom to the configuration file and copying it to the startup configuration file. To set the configuration register to hex 2101, which would yield binary 0001 in the boot field, the config-register 0x2101 global configuration command would be used. A third method, not mentioned in the chapter, includes removing the Flash memory in a router and then reloading.
24. What is the process used to update the contents of Flash memory so that a new IOS in a file called c4500-d-mz.120-5.bin on TFTP server 18.104.22.168 is copied into Flash memory?
Answer: copy tftp flash. The other details—namely, the IP address of the TFTP server and the filename—are requested through prompts to the user.
25. Name three possible problems that could prevent the command boot system tftp c2500-j-l.112-14.bin 22.214.171.124 from succeeding.
Answer: The possible reasons include: 126.96.36.199 is not accessible through the network, there is no TFTP server on 188.8.131.52, the file is not in the TFTP default directory, the file is corrupted, a different boot command could precede this boot command in the configuration file, meaning that the IOS referenced in the first boot command would be used instead.
26. Two different IOS files are in a router's Flash memory: one called c2500-j-l.111-3.bin and one called c2500-j-l.112-14.bin. Which one does the router use when it boots up? How could you force the other IOS file to be used? Without looking at the router configuration, what command could be used to discover which file was used for the latest boot of the router?
Answer: The first IOS file listed in the show flash command is the one used at reload time, unless a boot system command is configured. The configuration command boot system flash c2500-j-l.112-14.bin would override the IOS's decision to look for files in order in Flash memory. show version is the command used to display the filename of IOS
for the latest reload of a router. The show version output tells you the version as well as the name of the file that was used at last reload time. It is particularly difficult to find in the output of the command.
27. Is the password required at the console the same one that is required when Telnet is used to access a router?
Answer: No. The Telnet (virtual terminal) password is not the same password, although many installations use the same value.
28. Which IP routing protocols could be enabled using setup? Answer: RIP and IGRP.
29. Name two commands used to view the configuration to be used at the next reload of the router. Which one is a more recent addition to IOS?
Answer: show config and show startup-config. show startup-config is the newer one and, hopefully, is easier to remember.
30. Name two commands used to view the configuration that currently is used in a router. Which one is a more recent addition to IOS?
Answer: write terminal and show running-config. show running-config is the newer command and, hopefully, is easier to remember.
31. True or false: The copy startup-config running-config command always changes the currently used configuration for this router to exactly match what is in the startup configuration file. Explain.
Answer: False. Some configuration commands do not replace an existing command but simply are added to a list of related commands. If such a list exists, the copy startup-config running-config command simply adds those to the end of the list. Many of these lists in a router configuration are order dependent.
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