Answers and Explanations
A1: Answers: A, C, and D. Command-line interfaces can be established through a Telnet session, modem connection, and console connection. B is incorrect. Although TFTP is used to load a new IOS image onto a router, it does not allow you to establish a command-line interface session. E is incorrect, as FTP sessions are not used to establish command-line interface sessions with Cisco routers.

A2: Answer: B. All Catalyst switches perform basic switching functions. However, a setup menu similar to a router shows up on the screen. A is incorrect because the switch does not have an IP address or a default gateway installed in order to contact a TFTP server. C is incorrect because Catalyst switches rely on their default configuration on power-up and do not autosense the LAN configuration. D is incorrect because no passwords are set on the switch when it is turned on for the first time.

A3: Answer: B. When a Cisco router is first powered on, it performs a Power On Self Test, or POST, to ensure that its hardware is functioning properly. A is incorrect, as the Cisco IOS image is loaded after the post. C and D are incorrect, as they both take place after the IOS image is loaded.

A4: Answer: B. Communications software should be configured to communicate at 9600bps, with 8 data bits, 1 stop bit, no parity, and no flow control. A is incorrect because hardware flow control should not be configured. C and D are incorrect; the bps setting should be 9600, not 56000.

A5: Answer: C. For remote configuration, you connect a modem to the device's AUX port. A is incorrect; the console port is used for local configuration changes. B is incorrect, as the Eth0/0 interface does not support remote configuration via a modem. D is incorrect, as the Ser0/0 interface does not support remote configuration via a modem.

A6: Answers: A, B, and D. Configuration changes can be made through a Telnet session established with the router. B is correct, as configuration files can be downloaded from a TFTP server. Additionally, D is correct; network management applications such as CiscoWorks2000 also facilitate the downloading of configuration files. C is incorrect, as command-line sessions cannot be established through TFTP.

A7: Answer: A. User EXEC level contains a limited number of commands to allow basic monitoring. B, C, and D are incorrect, as they are not actual EXEC levels.

A8: Answer: C. The command mode that allows full access to all router commands is the Privileged EXEC level. A, B, and D are all fictitious command modes.

A9: Answer: C. The Enter key is used when configuring a router to parse and execute the typed command. A is incorrect, as the Tab key doesn't submit the command to the router; it merely autocompletes a partially entered command. B and D are incorrect, as neither the Esc key nor the F1 key is used to parse and execute commands.

A10: Answer: B. The hostname> prompt indicates the router is in User EXEC mode. A and D are incorrect, as they are not valid indicators of an EXEC mode. C is incorrect, as it indicates the user is in Privileged EXEC mode.

A11: Answer: A. Telnet traffic is not encrypted, so passwords are sent in plain text. B is incorrect, as Telnet uses no encryption. Passwords can be changed in a Telnet session, so C is incorrect. D is incorrect as well, as passwords are indeed usable during a Telnet session.

A12: Answer: C. The hostname# prompt indicates the router is in Privileged EXEC mode. A and D are incorrect, as they are not valid indicators of an EXEC mode. B is incorrect, as it indicates the user is in User EXEC mode.

A13: Answer: C. Entering ? at the prompt reveals the command options available to the user. A is incorrect, as entering help explains how to use the help feature. B and D are invalid commands.

A14: Answer: C. The disable command returns a user from Privileged EXEC mode to User EXEC mode. A is incorrect and typically ends the Telnet session. B is an invalid command. D is also incorrect and ends the Telnet session without returning the user to User EXEC mode.

A15: Answer: B. The proper syntax to show all commands beginning with the letter c is c?. A is incorrect, as entering show c attempts to execute a command; however, c is ambiguous, and the device returns an error message. C is also incorrect and has the same result; entering c ? attempts to show help, but c by itself is not specific enough to indicate a single command on the device and returns an error message. D is incorrect, as it is an invalid command.

A16: Answer: B. To assign a name to your switch, use the hostname command, followed by the name you want to assign. A is incorrect and is an invalid command. C and D are also incorrect and result in error messages on the device.

A17: Answer: B. Unless the switch is configured as an IP router, a default gateway must be configured. A is incorrect; your connection is not using the console port. C is correct, as a hostname is not required to configure the switch. D is incorrect; SNMP is used for remote management but is not required for you to configure a switch from a remote subnet.

A18: Answer: A. The show version command displays the switch's hardware configuration, as well as configuration files in use and boot images. The show version command also shows the switch's uptime. B is incorrect, but it is a valid command for showing the active configuration of the switch. C and D are invalid commands and result in error messages.

A19: Answer: B. The show running-config command displays the device's current active configuration. A is incorrect and results in an error message on the device. C and D are invalid commands that return error messages when entered.

A20: Answer: C. The show interfaces command displays statistics and status information on the interfaces of a switch. A is incorrect; the show version command displays the switch's hardware configuration, as well as configuration files in use and boot images. B and D are invalid commands.

A21: Answer: D. On a Catalyst switch, the show interface vlan 1 command displays information such as the IP address and subnet mask. A and C are incorrect and result in error messages. B is used on Microsoft operating systems to show the IP configuration.

A22: Answer: B. A new router enters a setup mode initially on its first boot. This creates a configuration file to be used when the router starts up again. A is incorrect. Although a switch can function with a default configuration, router configurations vary too greatly to allow a default configuration to work in most networks. C is incorrect, as the router initially looks in NVRAM for its configuration. D is incorrect because the router does not autosense and configure itself; it requires user interaction.

A23: Answer: C. Ambiguous command indicates that you are using an abbreviation but did not specify enough characters for the IOS to determine which command you intended. A is incorrect. If you do not specify enough parameters, for instance, you receive the % Incomplete command error. B is incorrect, as typographical mistakes result in the % Invalid input detected at '^' error. D is incorrect, as attempting to configure a nonexistent interface results in an % Invalid input detected at '^' error, as well.

A24: Answers: A and B. Ctrl+P and the up arrow both display the last command entered. Continue to use these keys to scroll through prior commands entered before the most recent command. Esc does not display prior commands, and the Tab key completes a command that you have begun typing, as long as it is not ambiguous.

A25: Answer: C. The terminal history size command sets the buffer for the current session only. A and B are invalid commands. D is incorrect; history size is a valid command, but it permanently changes the buffer size instead of changing it for the session only.

A26: Answer: C. The show version command shows the device's uptime. A is incorrect because show running-config shows the router's current active configuration. B and D are incorrect as well; show statistics and show uptime each display errors for invalid commands.

A27: Answer: C. RAM stores routing tables and the running configuration. A is incorrect, as NVRAM stores the startup configuration and is writable permanent storage. B is incorrect because flash memory is used for storage of the Cisco IOS, backup configurations, and other files. D is incorrect, as the IOS is the operating system of the router.

A28: Answer: A. NVRAM stores the startup configuration and is writable permanent storage. B is incorrect; Flash memory is used for storage of the Cisco IOS, backup configurations, and other files. C is incorrect because RAM stores routing tables and the running configuration. D is incorrect, as the IOS is the operating system of the router.

A29: Answer: B. Flash memory is used for storage of the Cisco IOS, backup configurations, and other files. A is incorrect because NVRAM stores the startup configuration and is writable permanent storage. C is incorrect, as RAM stores routing tables and the running configuration. D is incorrect because the IOS is the operating system of the router.

A30: Answer: B. Sub-interface mode allows you to configure virtual interfaces on a physical interface. A is incorrect because Interface mode supports commands on a per-interface basis. C is incorrect, as Line mode supports commands that configure the operation of a terminal line. D is incorrect; this prompt indicates that you are in Global Configuration mode.

A31: Answer: A. configure terminal is the correct command to enter Global Configuration mode. B and C are invalid commands and result in error messages. D is incorrect; this is a valid command, but it seeks configuration information from a network source instead of taking you into Global Configuration mode.

A32: Answer: C. Line mode supports commands that configure the operation of a terminal line as well as virtual terminal ports. A is incorrect, as Interface mode supports commands on a per-interface basis. B is incorrect, as Sub-interface mode allows you to configure virtual interfaces on a physical interface. D is incorrect, as this prompt indicates that you are in Global Configuration mode.

A33: Answer: E. As long as you haven't saved the running-config and any changes, reloading the router causes it to reboot and load the startup-config without any changes. C is a valid command, but incorrect. Copying the startup-config to the current running-config restores the router's configuration; however, if you have made a new configuration setting that won't be overwritten by the conflicting startup-config setting, it remains and is not overwritten. Instead, it is merged. A is an invalid command. B is a valid command, but it's the opposite of what you want to accomplish: It takes the current configuration in use and makes it the default startup configuration. D is incorrect because you can perform the desired operation from the command line.

A34: Answer: B. enable secret is the command used for creating encrypted passwords for Privileged EXEC mode. A is incorrect; enable password creates an unencrypted password. C and D are not valid IOS commands and result in error messages.

A35: Answer: B. The banner motd command creates a login message. The # symbol is a delimiter, indicating the start and end of your message. A is incorrect and results in an invalid command error message; it is missing the motd portion of the command. C is incorrect, as it does not follow the proper syntax by using the banner portion of the command. D is invalid, as there is no login command to create a login banner.

A36: Answer: D. line vty controls Telnet access, and password cisco is the correct syntax to set the password to cisco. A is incorrect, as line console controls console access. B is incorrect because enable secret is used not for Telnet access, but to control access to Privileged EXEC mode. C is incorrect, as line console is for console sessions, and enable secret is for setting the Privileged EXEC mode password.

A37: Answer: A. The logging synchronous command keeps console messages from interrupting, resulting in a more readable console session. B, C, and D are invalid commands that all result in error messages.

A38: Answer: B. exec-timeout 0 0 disables the timeout feature for sessions. A is incorrect; although using no with a command often disables it, there is no timeout command. C is incorrect as well, resulting in an invalid command error. D also is an invalid command. Although disable is a valid command for exiting Privileged EXEC mode, no disable does not achieve the desired goal.

A39: Answer: A. The proper format is interface type slot/port. B is incorrect; the correct syntax includes the term interface. C is incorrect, as interface is not used, and port numbering starts with 0. D is incorrect because although it uses the interface command, the port should be 0, not 1.

A40: Answer: B. The correct syntax of the command is clock rate bps. A and C are incorrect, as they do not use the proper syntax. D is incorrect because although the proper syntax is used, 2.4 does not set the bps to 2400 as required.

A41: Answer: A. In Interface Configuration mode, the no shutdown command re-enables the interface. B is incorrect; this command enters Privileged EXEC mode. C is incorrect because you don't need to specify the interface when you are in Line Configuration mode. D is incorrect; the enable command is not the proper command to achieve this goal.

A42: Answer: D. If both the interface and line protocol are down, there is a cable or interface problem. A is incorrect because the interface and line protocol are functioning fine. B is incorrect because if the interface is down, the line protocol cannot be up. C is incorrect; this indicates a clocking or framing problem.

A43: Answer: C. This situation indicates a clocking or framing problem. A is incorrect because the interface and line protocol are functioning fine. B is incorrect; if the interface is down, the line protocol cannot be up. D is incorrect because if both the interface and line protocol are down, there is a cable or interface problem.

A44: Answer: A. The administrator has issued the shutdown command. B is incorrect because if the interface is down, the line protocol cannot be up. C is incorrect, as this indicates a clocking or framing problem. D is correct because if both the interface and line protocol are down, there is a cable or interface problem.

A45: Answer: D. The show controller command shows the type of cable connected to the interface. This information is gathered when the router starts up. A is incorrect; the command does not exist. B is incorrect; show interface does not show the type of cable connected. C is incorrect. The running-configuration command does not show the type of cable connected.

A46: Answer: A. The media-type command specifies settings such as aui, 10base-t, and 100base-t and might need to be set if it is not autodetected. B, C, and D are invalid commands that result in errors.

A47: Answer: D. The clock rate needs to be set on the DCE device. A is incorrect because only the DCE device should be set. B is incorrect, as the DCE device must be configured with a clock rate. C is incorrect; the DCE, not the DTE device, needs to have the clock rate set.

A48: Answer: D. The service password-encryption command allows you to use encrypted passwords. A, B, and C are invalid commands that result in error messages when used in the command-line interface.

A49: Answer: B. This is Interface Configuration mode, used to change settings for a specific interface, including the IP address assigned to a specific interface. A is incorrect; this is Global Configuration mode, used for router-wide settings. C is a fictitious router mode. D is Line Configuration mode, used to configure the console or Telnet sessions.

A50: Answer: A. This is Global Configuration mode, used for router-wide settings, such as the hostname, or the message of the day. B is Interface Configuration mode, used to change settings for a specific interface. C is a fictitious router mode. D is Line Configuration mode, used to configure the console or Telnet sessions.