Using Multiple Authentication Methods

• AAA authentication allow multiple servers & multiple authentication methods.
• So user can be authenticated even if one authentication method is not working.
• The aaa authentication command supports up to four methods on a single command.
• No limit to the number of RADIUS or TACACS+ servers that can be referenced.
• Logic used by IOS when using these methods are:
• Based on the 1st listed method first, if that methode not respond, move to the next & then next & so on until a method responds. Use the first- responding-server's decision (allow or reject).
• If no response occurs for any method, reject the request.
•