Chapter 2

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

All end devices and network devices require an ______________.

Operating system

The user can interact with the shell using __________________ or a ______________.

-command-line interface -graphical user interface

The structure of an IPv4 address is called ____________ and is represented by ______________.

-dotted decimal notation -four decimal numbers between 0 and 255

Through a GUI, a PC operating system enables a user to do the following:

-use a mouse to make selections and run program -enter text and text-based commands -view output on a minitor

What do terminal emulation programs do?

Allow you to enhances your productivity by adjusting window sizes, changing font sizes, and changing color schemes.

subnet mask

An IPv4 subnet mask is a 32-bit value that differentiates the network portion of the address from the host portion. Coupled with the IPv4 address, the subnet mask determines to which subnet the device is a member.

The family of network operating systems used on many Cisco devices is called the __________________.

Cisco Internetwork Operating System (IOS)

GUI

Graphical User Interface

IPv4 addresses are assigned to ______________.

Individual devices connected to a network

The portion of the OS that interacts directly with computer hardware is known as the __________________.

Kernel

OS

Operating system

Secure Shell (access method)

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.

SSH

Secure Shell

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

Shell

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.

ping ip-address

The command is ping and the user-defined argument is the ip-address of the destination device. For example, ping 10.10.10.5.

traceroute ip-address

The command is traceroute and the user-defined argument is the ip-address of the destination device. For example, traceroute 192.168.254.254.

default gateway

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

Hardware

The physical part of a computer including underlying electronics

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.

Console (access method)

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.

running-config

This is stored in Random Access Memory (RAM). It 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.

startup-config

This is the saved configuration file that is stored in NVRAM. It contains all the commands that will be used by the device upon startup or reboot. Flash does not lose its contents when the device is powered off.

Virtual terminal lines enable remote access using Telnet or SSH to the device. Many Cisco switches support up to 16 VTY lines that are numbered 0 to 15. True or false?

True

CLI

command-line interface

Kernel

communications between the hardware and software of a computer and manages how hardware resources are used to meet software requirements

The operating system on home routers is usually called _________________.

firmware

To secure user EXEC mode access, enter line console configuration mode using the ________________ global configuration command.

line console 0

How to enter VTY mode?

line vty 0 15

VTY

virtual terminal