OS Components & Resource Management

• Module 2 covers basic switch and end device configuration

Module Objectives

• Implement initial settings on network switches and end devices
• Settings include passwords, IP addressing, and default gateway parameters

Cisco IOS Access

• Explain how to access a Cisco IOS device for configuration
• Explain how to navigate Cisco IOS to configure network devices

IOS Navigation

• Describe the command structure of Cisco IOS software
• Configure a Cisco IOS device using CLI

Basic Device Configuration

• Use IOS commands to save the running configuration

Save Configurations

• Explain how devices communicate across network media
• Configure a host device with an IP address

Ports and Addresses

• Verify connectivity between two end devices

Configure IP Addressing

• The shell is the user interface letting users request tasks, done via CLI or GUI
• The kernel communicates between hardware and software, managing hardware resources
• Hardware is the physical components of a computer, including electronics
• A GUI allows user interaction with graphical icons, menus, and windows
• GUIs are user-friendly but can fail, so network devices often use CLI
• A PC operating system enables using a mouse, entering text commands, and viewing output
• A CLI-based network OS enables using a keyboard for commands and viewing output

Access Methods

• Console: Physical management port for device access, such as initial configuration
• Secure Shell (SSH): Secure remote CLI connection over a network
• Telnet: Insecure remote CLI connection over a network, sends data in plaintext

Terminal Emulation Programs

• Terminal emulation programs connect to network devices via console or SSH/Telnet
• Examples of programs: PuTTY, Tera Term, and SecureCRT

IOS Navigation: Primary Command Modes

• User EXEC Mode: Limited access, basic monitoring commands
• Indicates the CLI prompt that ends with the > symbol
• Privileged EXEC Mode: Access to all commands and features
• Identified by the prompt that ends with the # symbol

Configuration Mode and Subconfiguration Modes:

• Global Configuration Mode: Used to access configuration options on a device
• Line Configuration Mode: Used to configure console, SSH, Telnet, or AUX access
• Interface Configuration Mode: Used to configure a switch port or router interface

Navigation Between IOS Modes

• Move from user EXEC to privileged EXEC with the enable command
• The configure terminal command is used to move in and out of global configuration mode
• The exit command is used to return to privilege EXEC mode
• The line command is used to move in and out of line configuration mode
• Exit command returns to global configuration mode
• The exit command gets back to global configuration mode from a subconfiguration mode
• End command (or Ctrl+Z) returns to privilege EXEC mode
• Moving from one subconfiguration mode to the other: type the desired subconfiguration command

Command Structure

• The basic IOS command structure consists of the prompt, command, a space, and either a keyword or argument
• A keyword is a parameter defined in the operating system
• An argument is a value defined by the user

IOS Command Syntax Check

• Command syntax provides the format that must be used when entering a command
• Boldface indicates commands and keywords entered as shown
• Italic text indicates arguments provided by the user
• Square brackets ([x]) indicate an optional element
• Braces ({x}) indicate a required element
• Braces and vertical lines within square brackets ([x {y | z }]) indicate a required choice within an optional element
• The ping command requires the ip-address argument
• The traceroute command requires the ip-address argument

IOS Help Features

• Context-sensitive help provides quick answers to questions
• Available commands in each command mode
• Commands starting with specific characters
• Available arguments/keywords for commands
• Command syntax check verifies if a valid command was entered

Hot Keys and Shortcuts

• The IOS CLI provides hot keys and shortcuts
• Commands/keywords can be shortened to the minimum characters for unique identification

Basic Device Configuration

• The first configuration command is the hostname command
• Naming guidelines devices
• Start with a letter
• No spaces
• End with a letter or digit
• Use letters, digits, dashes
• Less than 64 characters
• Use the no hostname global config command to return to default prompt

Password Guidelines

• Weak passwords are a security concern
• All networking devices should limit administrative access with passwords and encrypt them
• Passwords should be more than eight characters, with mixed case, numbers, and special characters
• Avoid common words and avoid reusing passwords
• The labs use simple passwords, such as 'cisco' or 'class', which is an example of what should be easily guessable passwords

Configure Passwords

• Securing user EXEC mode access:
• Enter line console configuration mode with line console 0 in global config
• Specify the user EXEC mode password using the password password command
• Enable access using the login command
• Securing privileged EXEC mode access:
• Enter global configuration mode, then use the enable secret password command
• First enter VTY
• Configuration mode using
• The line vty 0 15 command in
• Global configuration mode and next, specify the VTY
• Password using the password

Encrypt Passwords

• Startup-config and running-config files show passwords in plaintext
• Useservice password-encryption in global config to encrypt all plaintext passwords
• To verify, use show running-config command
• To warn unauthorized personnel, use the banner motd # message # global config command
• The # is a delimiting character and will be entered before the message and again after the messsage

Save Configurations

• There are two system files that store the device configuration
• Startup-config: Saved configuration file in NVRAM, contains commands used upon startup/reboot, and flash doesn't lose content when powered off
• Running-config: Stored in RAM, reflects the current configuration, modifying affects device operation immediately, and RAM is volatile (loses content when restarted)
• To save the running configuration to startup configuration file, use copy running-config startup-config in privileged EXEC mode
• The steps to alter running configurations are, remove the changed commands, and reload the device using the reload command
• It erases startup config using the erase startup-config command, reload the running config from RAM

Capture Configuration to a Text File

• To achieve this, you need open a terminal emulation software, enable logging in terminal software, and assign a file location and name to the save log file Step 3 is: The show running config or, show startup config command is to be executed at the privileged EXEC mode. It displays the terminal window to the chosen file
• It disables it by choosing none from the session logging option

Ports and Addresses

• IP addresses let devices locate each other for communication on the internet
• IPv4 addresses use dotted decimal notation (four numbers between 0 and 255
• IPv4 subnet mask is a 32-bit value differentiating the network/host portions
• Coupled with an IPv4 address, the subnet mask shows which subnet the device is a member of
• Default gateway address is the IP of the router that accesses remote networks Ipv6 adressses are 128 bit and are written with hexadecimal values
• Interfaces and ports are, network communication depends on end user device and network device interface and the cable that connects them

Congfigure IP addressing

• Dynamic Host Configuration Protocol configuration (DHCP), end devices on the network will need a IP address to communicate wiht other devices and the network
• Ipv4 addres information can be eentered in end devices maunally, or auto or automatically using Dynamic Host Configuration Procotol
• To configure on a windows Pc, open to the control panel > network sharing center > and change adapter settings
• Click properties to open the intranet protocol version 4
• IPv6 uses DHCPv6, adn SLAAC for dynamic address allocation

Switch Virtual Interface

• Enter the interface vlan1 command in global configuration and assign an Ipv4 next address using the Ip address subnet masked command

Hot Keys and Shortcuts covered in a video

• Tab key( Tab completion)
• Command Shortening
• Up and down arrow key
• CTRL + C
• CTRL + Z,
• CTRL +Shift+6,
• CTRL +R