Banner, what is that?

One of the things that usually are not implemented by the network administrator is the banner; but what and why use it? The banner is a feature used not only on Cisco systems but also in other systems like Unix, Linux and so on. It permits to define a text that it is displayed in some cases, for example when you log in a router via SSH. There are two main reasons to implement banner on our router/switch: Banner messages should be used to warn would-be intruders that they are not welcome on your network. Banner are useful to quickly [...]