The command aaa authentication login default group ISE local configures the Cisco Nexus Series Switch to use TACACS+ for authentication by default and specifies a fallback to local authentication if the TACACS+ server becomes unavailable. This ensures that users are authenticated against the TACACS+ server when it is available, but allows them to use local switch credentials if the server cannot be reached, meeting the requirement for failover to local account1.
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* Cisco documentation on configuring TACACS+ for Cisco Nexus Series Switches provides detailed steps and explanations for setting up authentication and ensuring failover to local accounts