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.
Sometimes people get confused when it comes to telling how much memory the router has and which memory does what. There are 4 memory terms you should be familiar with, and 2 of these should be checked before upgrading the router’s IOS.
The Routing Information Protocol (RIP) is the most basic distance-vector routing protocol in use these days. It has been designed for small and local networks and because it’s configuration is very simple, it’s still commonly used. By default, RIP sends out it’s entire routing table every 30 seconds. While in small networks with few routes in the routing table this is not an issue and RIP can route efficiently; in larger networks with many routers and routes this routing update would cause unnecessary network traffic. You can read more about RIP in the document RFC 2453.
Having user accounts on a router makes life and logging much easier. We can assign different privilige levels to different users to restrict access to certain commands. You may want a junior admin to see a few things to help you troubleshoot but you don’t want him to be able to change anything. In the following example we are going to add 2 local user accounts, one with the default privilege level (0) and one with full privilege level (15).
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.