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Configure a network operating system

34 important questions on Configure a network operating system

WHat is known as the shell of an OS?

The portion that interfaces with applications and the user is known as the shell.

Name two ways the user can interact with the shell.

1. using the command-line interface (CLI)
2. using the graphical user interface (GUI)

Why would you want to access a network device via CLI instead of GUI?

GUIs may not always be able to provide all of the features available at the CLI. GUIs can also fail, crash, or simply not operate as specified. The CLI is less resource intensive and very stable when compared to a GUI.

What's the advantage of using a console port to acces a Cisco networking device to acces the CLI interface?

The advantage of using a console port is that the device is accessible even if no networking services have been configured, such as when performing an initial configuration of the networking device. When performing an initial configuration, a computer running terminal emulation software is connected to the console port of the device using a special cable. Configuration commands for setting up the switch or router can be entered on the connected computer.

Why is SSH the recommended method for remote management of your cisco network device?

SSH is the recommended method for remote management because it provides a secure connection. SSH provides encrypted password authentication and transport of session data. This keeps the user ID, password, and the details of the management session private. Most versions of Cisco IOS include an SSH server and an SSH client that can be used to establish SSH sessions with other devices.

Why should you not use Telnet to acces your remote Cisco networking device?

Telnet does not provide a securely encrypted connection. User authentication, passwords, and commands are sent over the network in plaintext.
Best practice dictates to use SSH instead of Telnet for remote management CLI connections. Cisco IOS includes a Telnet server and a Telnet client that can be used to establish Telnet sessions with other devices.

What does User EXEC Mode do?

This mode has limited capabilities but is useful for basic operations. It allows only a limited number of basic monitoring commands but does not allow the execution of any commands that might change the configuration of the device. The user EXEC mode is identified by the CLI prompt that ends with the > symbol.

- Mode allows access to only a limited number of basic monitoring commands.
- it is often referred to as "view-only" mode.

Default Device Prompt: Switch>

What does Privileged EXEC Mode do?

To execute configuration commands, a network administrator must access privileged EXEC mode. Higher configuration modes, like global configuration mode, can only be reached from privileged EXEC mode. The privileged EXEC mode can be identified by the prompt ending with the # symbol.

- Mode allows access to all commands and features.
- The user can use any monitoring commands and execute configuration and management commands.

Default Device Prompt: Switch#

How is global configuration mode identified by a promt?

Global configuration mode is identified by a prompt that ends with (config)# after the device name, such as Switch(config)#.

Name two common subconfigutation modes that are accessed after the global configuration mode is accessed?

Line Configuration Mode - Used to configure console, SSH, Telnet, or AUX access.

Interface Configuration Mode - Used to configure a switch port or router network interface.

Name a different name to call Privileged EXEC mode

enable mode

Explain how to enter and exit a sub-configuration mode.

To enter line sub-configuration mode, you use the line command followed by the management line type and number you wish to access. To exit a sub-configuration mode and return to global configuration mode, use the exit command.

What command is used to move from any sub-configuration mode of the global configuration mode to the mode one step above it?

exit

What command is used to move from any sub-configuration mode to the privileged EXEC mode?

end, or the key combination Ctrl+Z

Explain keyword (IOS Command Structure).

a specific parameter defined in the operating system (in the figure, ip protocols)

Explain argument. (IOS Command Structure)

not predefined; a value or variable defined by the user (in the figure, 192.168.10.5)

What command is used to enable Context-sensitive help?

enter a question mark ? at the CLI

Name the steps needed to apply a new host name to a switch.

- enable (from user EXEC mode to priviliged EXEC mode)
- configure terminal (from priviliged EXEC mode to global configuration mode)
- hostname [new name of switch] (change hostname from grlobal configuration mode)

Explain the steps to set a password to access the user EXEC mode.

To secure the user EXEC access, the console port must be configured.

1. enable (from user EXEC mode to priviliged EXEC mode)
2. configure terminal (from privileged EXEC mode to global configuration mode)
3. line console 0 (from global configuration mode to line console configuration, 0 represents the first and in most cases the only console interface)
4. password [password] (specify the user EXEC mode password from line console configuration)
5. login (Console access will now require a password before gaining access to the user EXEC mode.

What do Virtual terminal (VTY) lines do?

they enable remote access to the device via SSH and Telnet

Explain the steps to secure VTY lines.

1. enable (from user EXEC mode to priviliged EXEC mode)
2. configure terminal (from privileged EXEC mode to global configuration mode)
3. line vty 0 15 (from global configuration mode to VTY mode, many Cisco switches support up to 16 VTY lines that are numbered 0 to 15)
4. password [password] (specify the VTY password from VTY mode)
5. login (VTY access will now require a password before gaining access to the VTY mode.

What command is used to encrypt passwords and explain the command?

service password-encryption global config command.

The command applies weak encryption to all unencrypted passwords. This encryption applies only to passwords in the configuration file, not to passwords as they are sent over the network. The purpose of this command is to keep unauthorized individuals from viewing passwords in the configuration file.

What command is used to cerify that passwords are encrypted?

show running-config (in priviliged EXEC mode)

What command is used to create a banner message on a network device?

banner motd # [the message] #

The “#” in the command syntax is called the delimiting character. It is entered before and after the message. The delimiting character can be any character as long as it does not occur in the message. For this reason, symbols such as the "#" are often used. After the command is executed, the banner will be displayed on all subsequent attempts to access the device until the banner is removed.

Which two system files store the device configuration?

startup-config - The file stored in Non-volatile Random Access Memory (NVRAM) that contains all of the commands that will be used by the device upon startup or reboot. NVRAM does not lose its contents when the device is powered off.

running-config - The file stored in Random Access Memory (RAM) that reflects the current configuration. Modifying a running configuration affects the operation of a Cisco device immediately. RAM is volatile memory. It loses all of its content when the device is powered off or restarted.

How do you save changes made to the running configuration file to the startup configuration file?

copy running-config startup-config (privileged EXEC mode)

If power to the device is lost or if the device is restarted, all configuration changes will be lost unless they have been saved.

What command is used to clear all the configurations?

clearing all the configurations require erasing the startup configuration and restarting the device. The startup configuration is removed by using the erase startup-config privileged EXEC mode command. After the command is issued, the switch will prompt you for confirmation. Press Enter to accept.

After removing the startup configuration from NVRAM, reload the device to remove the current running configuration file from RAM. On reload, a switch will load the default startup configuration that originally shipped with the device.

Explain what an IPv4 subnet mask is.

With the IPv4 address, a subnet mask is also necessary. An IPv4 subnet mask is a 32-bit value that separates the network portion of the address from the host portion. Coupled with the IPv4 address, the subnet mask determines which particular subnet the device is a member.

What is the default gateway and what is it used for by the host?

The default gateway address is the IP address of the router that the host will use to access remote networks, including the Internet.

What does 'a virtual interface' mean?

A virtual interface means that there is no physical hardware on the device associated with it.

What does DNS stand for and what's its use?

The DNS server addresses are the IPv4 addresses of the Domain Name System (DNS) servers, which are used to translate IP addresses to domain names, such as www.cisco.com.

Explain the steps needed to configure an SVI on a switch?

1. enable (from user EXEC mode to privileged EXEC mode)
2. configure terminal (from privileged EXEC mode to global configuration mode)
3. interface vlan 1 (from global configuration mode to SVI mode, Vlan 1 is not an actual physical interface but a virtual one)
4. ip address [op-address subnet-mask] (interface configuration command)
5. no shutdown (enable the virtual interface)

What command is useful for verifying the condition of the switch interfaces?

show ip interface brief

What is the ping command used for?

The ping command can be used to test connectivity to another device on the network or a website on the Internet.

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CCNA 1

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