you are referencing the globally configured TACACS+ and RADIUS servers. If you have defined a custom group of either type, you can reference the group name you created with the aaa servers com- mand. For example, earlier we created a Login-Servers group. To reference this group in a method list, we would include the group name after the keyword group: aaa authentication login default group Login-Servers This example includes the default method, which, when implemented, is automati- cally applied to all interfaces. If you're relying on external servers, and problems are encountered, you can some- times lock everyone out of the router. The none method allows anyone to access the router without authenticating. When the none method is included as the last method in a list, anyone will be able to access the router in the event that all other authenti- cation methods fail: aaa authentication login default group tacacs+ local none Again, failure is defined here as failed communication with the server listed, not an incorrect password entry. Of course, including none can be dangerous, as it means that a malicious party can launch a denial-of-service attack on the authentication servers, and thereby gain access to your devices (which is counterindicated by most network administrators). Instead, I like to use local-case as the last method in my method lists: aaa authentication login default group tacacs+ local-case Chapter 24: Authentication in Cisco Devices I like to configure on all routers a standard username and password that will only be needed in the event of a server or network failure. I feel slightly better about using local-case than local, as it means I can include both upper- and lowercase charac- ters in the usernames and passwords. Be careful, though, as this practice is frowned upon in environments where credit card transactions occur. Payment Card Industry (PCI) compliance dictates many details about how user data is stored and accessed. You can use the same method list name for both PPP and login authentic