James

There are several ways to configure AAA so that you are not locked out if the server is not available. You can use a locally configured user name, as you suggest here, or you can use the configured line passwords.

To use a locally configured user your configuration might look something like this:

user rick password cisco

aaa authentication login default group tacacs+ local

Or to use the line passwords as a backup your config might look something like this:

aaa authentication login default group tacacs+ line

You also probably need a backup for access to privilege mode. This is usually done using the locally configured enable secret. To do this the configuration might look something like this:

aaa authentication enable default group tacacs+ enable

HTH

Rick