How to configure SSH on a Cisco Router
We need configure SSH on a Cisco router or switch in order to access it remotely, unless we’re using an access server. Even then, SSH should be configured in case the access server fails.
In this example we will configure PPP authentication with an alternate method. We are going to instruct the router to send different credentials (other than it’s own hostname) to the other side. In contrast to the previous method, this works even if you change the routers name.
By configuring authentication on our serial interfaces, we can restrict access to our router. This is not just useful, but it is highly recommended to implement authentication and a high level of security on all devices whenever possible, especially the ones facing the Internet.