aaa authentication enable default enable

[Iloveyou]

How will a switch behaves if:

I configure neither "enable secret" or "aaa authentication enable default enable"
I configure "enable secret" without "aaa authentication enable default enable"

I realized that configuring "aaa authentication enable default enable" without enable secret results in %error in authentication.

[balaji.bandi]

Enabling Cisco AAA 'authentication enable' mode is significantly disruptive as former access methods are immediately disabled.

so order information is very important when you enabling the AAA commands. Since you have not saved the configuration, take the maintenance window and reload the device, so the AAA config you applied will be removed.

before enabling AAA read below the information can be find here :

https://learningnetwork.cisco.com/s/article/introduction-to-aaa-implementation

https://www.cisco.com/c/en/us/support/docs/security-vpn/terminal-access-controller-access-control-system-tacacs-/10384-security.html

[M02@rt37 · Accepted solution]

Hello @Iloveyou 

If neither the `enable secret` nor `aaa authentication enable default enable` is configured on a switch, then when you try to access privileged EXEC mode using the `enable` command, the switch does not prompt for a password. Because no password is set, it defaults to allowing access to privileged mode without any authentication. In essence, the switch behaves as if it is unsecured, permitting anyone to enter privileged mode simply by issuing the `enable` command, which is not recommended for a secure network environment.

When an `enable secret` is configured but `aaa authentication enable default enable` is not, the switch uses the `enable secret` password as the default method to control access to privileged EXEC mode. The `enable secret` sets the password that must be entered when using the `enable` command, providing a layer of security by requiring a password to access privileged commands. In this setup, since AAA is not being used for authentication of the `enable` command, the traditional method of using the `enable secret` takes precedence.

If `aaa authentication enable default enable` is configured without an `enable secret`, the switch attempts to use AAA to authenticate the `enable` command. However, without an `enable secret` or any other specified method for enable authentication, the switch is unable to verify the authentication request, resulting in an error message indicating an authentication failure (e.g., `% Error in authentication`). This situation occurs because the switch is set to use AAA for authentication, but there is no valid authentication mechanism configured to process the enable request, leaving the switch unable to grant access to privileged EXEC mode.