Notes on AAA Local Authentication Configuration

Introduction

• Discussion on configuring AAA local authentication.
• Focus on commands used for configuration, practice in future videos.

Importance of Local Database

• Always add at least one username in the local database for backup.
  • Ensures access if server fails.
  • Example: Router configuration with one username and password.

Enabling AAA Authentication

• Command to enable AAA: aaa new-model

Configuring Default Authentication List

• Configure default authentication list command: aaa authentication login default local
• Command Breakdown:
  • login: Allows user access via console or VTY terminals.
  • default: Applies to all lines (console, VTY, etc.).
  • local: Specifies the use of local database for authentication.

Authentication Methods Priority

• Authentication checks in order:
  1. TACACS+ server
  2. RADIUS server
  3. Local database
• Definitions:
  • Primary method: First server to check.
  • Backup method: Fallback if primary fails.

Applying Authentication List to Ports

• Example to apply authentication to VTY lines:
  • Command to access VTY line:
  line vty 0 4 login authentication default
  • Specify a unique name if desired (e.g., class name).

Secure Transport Configuration

• Command for secure communication only: transport input ssh
• Applicable to both VTY and console lines:
  • Command for console line:
  line console 0 login authentication default

Transition to Server-Based Authentication

• Requirement for a AAA server:
  • Dedicated machine to check user credentials.
• Command to enable AAA on routers: aaa new-model

Configuring AAA Server Information

• Specifying TACACS+ server's IP address: tacacs-server host [IP_ADDRESS]
• Define shared key for secure communication: key newbie123

Authentication List for Server-Based

• Command to create authentication list: aaa authentication login default group tacacs+ local
• Authentication priority:
  1. TACACS+ server
  2. Local database

Applying Server-Based Authentication

• Apply the defined list to VTY lines: line vty 0 4 login authentication default
• Secure transport input command: transport input ssh

Conclusion

• Summary of steps for configuring AAA local and server-based authentication.
• Future demonstration on implementation.