02_Basic Switch and End Device Configuration Flashcards
Operating Systems
he portion of the OS that interacts directly with computer hardware is known as the kernel. The portion that interfaces with applications and the user is known as the shell. The user can interact with the shell using a command-line interface (CLI) or a graphical user interface (GUI).
shell
the user interface that allows users to request specific tasks from the computer. These requests can be made either through the CLI or GUI interfaces
kernel
communicates between the hardware and software of a computer and manages how hardware resources are used to meet software requirements
hardware
physical part of a computer including underlying electronics
GUI
A GUI such as Windows, macOS, Linux KDE, Apple iOS, or Android allows the user to interact with the system using an environment of graphical icons, menus, and windows. The GUI example in the figure is more user-friendly and requires less knowledge of the underlying command structure that controls the system. For this reason, most users rely on GUI environments.
Purpose of an OS
Network operating systems are similar to a PC operating system. Through a GUI, a PC operating system enables a user to do the following:
- Use a mouse to make selections and run programs
- Enter text and text-based commands
- View output on a monitor
A CLI-based network operating system (e.g., the Cisco IOS on a switch or router) enables a network technician to do the following:
- Use a keyboard to run CLI-based network programs
- Use a keyboard to enter text and text-based commands
- View output on a monitor
Console
This is a physical management port that provides out-of-band access to a Cisco device. Out-of-band access refers to access via a dedicated management channel that is used for device maintenance purposes only. The advantage of using a console port is that the device is accessible even if no networking services are configured, such as performing the initial configuration. A computer running terminal emulation software and a special console cable to connect to the device are required for a console connection.
Secure Shell (SSH)
SSH is an in-band and recommended method for remotely establishing a secure CLI connection, through a virtual interface, over a network. Unlike a console connection, SSH connections require active networking services on the device, including an active interface configured with an address. Most versions of Cisco IOS include an SSH server and an SSH client that can be used to establish SSH sessions with other devices.
Telnet
Telnet is an insecure, in-band method of remotely establishing a CLI session, through a virtual interface, over a network. Unlike SSH, Telnet does not provide a secure, encrypted connection and should only be used in a lab environment. User authentication, passwords, and commands are sent over the network in plaintext. The best practice is to use SSH instead of Telnet. Cisco IOS includes both a Telnet server and Telnet client.
Which access method would be most appropriate if you were in the equipment room with a new switch that needs to be configured?
Console
Which access method would be most appropriate if your manager gave you a special cable and told you to use it to configure the switch?
Console
Which access method would be the most appropriate in-band access to the IOS over a network connection?
Telnet/SSH
Which access method would be the most appropriate if you call your manager to tell him you cannot access your router in another city over the internet and he provides you with the information to access the router through a telephone connection?
Aux
User EXEC Mode
- Mode allows access to only a limited number of basic monitoring commands.
- It is often referred to as “view-only” mode.
Switch>
Router>
Privileged EXEC Mode
- Mode allows access to all commands and features.
- The user can use any monitoring commands and execute configuration and management commands.
Switch#
Router#
Various commands are used to move in and out of command prompts. To move from user EXEC mode to privileged EXEC mode, use the enable command. Use the disable privileged EXEC mode command to return to user EXEC mode.
Note: Privileged EXEC mode is sometimes called enable mode.
global config mode
To configure the device, the user must enter global configuration mode, which is commonly called global config mode.
From global config mode, CLI configuration changes are made that affect the operation of the device as a whole. Global configuration mode is identified by a prompt that ends with (config)# after the device name, such as Switch(config)#.
Global configuration mode is accessed before other specific configuration modes. From global config mode, the user can enter different subconfiguration modes.
configure terminal
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.
To move from any subconfiguration mode of the global configuration mode to the mode one step above it in the hierarchy of modes…
…enter the exit command.
To move from any subconfiguration mode to the privileged EXEC mode…
…enter the end command or enter the key combination Ctrl+Z.
enable command
Privileged EXEC Mode
line console 0
- subconfiguration mode
- management interface for the console port
line vty 0 15
virtual terminal management
remote access
end command
exit out all of subconfiguration modes and return to privileged exec mode
Which IOS mode allows access to all commands and features?
privileged EXEC mode
Which IOS mode are you in if the Switch(config)# prompt is displayed?
global configuration mode
Which IOS mode are you in if the Switch> prompt is displayed?
user EXEC mode
Which two commands would return you to the privileged EXEC prompt regardless of the configuration mode you are in? (Choose two.)
- CTRL+Z
- end
Keyword
This is a specific parameter defined in the operating system (in the figure, ip protocols).
Argument
This is not predefined; it is a value or variable defined by the user (in the figure, 192.168.10.5).
boldface
Boldface text indicates commands and keywords that you enter literally as shown.
italics
Italic text indicates arguments for which you supply values.