Introduction to Networks - Module 2 Notes

Overview

• Focus on basic switch and end device configuration.
• Reference for Module 1 video provided in the description.
• Associated labs and videos will be linked below.

Module Objectives

• Implement initial settings on network devices (switches):
  • Passwords
  • IP addressing
  • Default gateway
• Learn about Cisco IOS access:
  • Command structure
  • Basic device configuration
  • Saving configurations
  • Verifying connectivity

Cisco IOS Access

• Cisco IOS: Operating system used on Cisco devices.
• Components of Cisco IOS:
  • Shell: User interface for task requests (CLI and GUI).
  • Kernel: Manages communication between hardware and software.
  • Hardware: Physical components like routers and switches.

GUI vs. CLI

• GUI (Graphical User Interface):
  • Easier for users, less technical knowledge required.
  • Examples: Windows, macOS, Linux.
  • Less ideal for network devices; CLI is preferred.
• CLI (Command Line Interface):
  • Used to interact with Cisco devices.
  • More flexible and powerful for network configurations.

Accessing Cisco IOS Console

• Access Methods:
  • Console: Out-of-band access for initial configurations.
  • SSH: Secure in-band connection; recommended for remote access.
  • Telnet: Insecure method, typically disabled in production environments.
  • Common terminal emulation programs: PuTTY, Tera Term, SecureCRT.

Cisco IOS Modes

• User Executive Mode: Limited commands; identified by the prompt symbol.
• Privilege Executive Mode: Full access to commands; identified by # symbol.
• Configuration Modes:
  • Global Configuration Mode: Basic device settings.
  • Line Configuration Mode: Configure lines like SSH/Telnet.
  • Interface Configuration Mode: Setup specific interfaces (e.g., switch ports).

Navigating Between Modes

• Commands to switch between modes:
  • From User to Privilege: enable or en
  • To Global Configuration: configure terminal or config t
  • To Line Configuration: line console 0
  • Use exit to exit modes.

Command Structure and Syntax

• Command syntax format: prompt command [keyword] [argument]
  • Keywords: Defined in the operating system.
  • Arguments: User-defined values.
• Examples of command syntax:
  • ping [ip address]
  • traceroute [ip address]
• Context-sensitive help: Use ? to see available commands or arguments.

Hotkeys and Shortcuts

• CLI shortcuts save time:
  • Use Tab for auto-completion.
  • Ctrl + P to recall previous commands.
  • Ctrl + C to exit commands or modes.
• Basic editing keys:
  • Backspace, left/right arrow keys for navigation.

Basic Device Configuration

• Hostnames: Unique names identifying devices.
  • Example: hostname SW-FLOW-1
• Passwords: Secure access to devices.
  • Best practices for choosing complex passwords.
• Password Configuration:
  • Use commands like line console 0, enable secret, service password encryption.
• Banner Messages: Inform users of unauthorized access warnings.
  • Example: banner motd #Authorized access only#

Configurations and Saving

• Startup Config: Saved in NVRAM; used on reboot.
• Running Config: Stored in RAM; volatile.
• Save running config to startup config: copy running-config startup-config.

IP Addresses and Addressing

• Purpose: Enable communication between network devices.
• IPv4 vs. IPv6:
  • IPv4: 32-bit address format.
  • IPv6: 128-bit address format, hexadecimal.
• Default Gateway: Router IP for accessing remote networks.

Configuration Methods

• Manual Configuration: Used for servers and critical infrastructure.
• DHCP: Automatic IP address assignment.
• Switch Virtual Interface (SVI): Configuring IP on switches using interface vlan 1.

Conclusion

• Remember key concepts for quizzes and exams:
  • IOS modes and navigation.
  • Basic configurations: hostnames, passwords, banners.
  • IP addressing requirements.
• Future videos will cover practical demonstrations of configurations.