Banners

You’re just giving someone a banner of information at a certain time when they are connecting to a router.

Now we’re going to create three different kinds of banners here.

We’re going to create a log in, a message of the day, and an exec banner… and really the only difference is where they appear when someone is going to Telnet in. So I’m going to take special note of that… and we’re going to take a look at this C banner-text too.

Let’s start with a log in banner. And this will be presented to someone before they authenticate, and we’ll Telnet in from R1 and test that after we write it.

But this is the one that you may actually have to write simply for legal reasons.

Let’s go ahead and look at Banner log in.

And here’s that line again.  “C” here means you can use any character as your delimiting character which simply means you’re indicating the beginning of your banner and the end of your banner.

The thing is you just have to use the same symbol for the beginning and the end. You don’t have to use the letter C. So let’s just go and use a “$” here and and it gives me a line to create and that’s it.

So notice once I entered banner log in and then the delimiting character I chose, which is the dollar sign. it’s going to tell you to enter the text message and end with the character dollar sign. That’s all there is to it.

So I’m just going to go with something short and sweet here, and then put a dollar sign right there and then hit enter again.

So let’s see is there a show banner command?

No there isn’t.

So what we will do instead is go over the R1, Telnet in,  and I still have everything on from the previous lab, and we should be able to telnet in…

And right there you can see the banner (unauthorized use prohibited).

I’ll go ahead and log in and then just log right back out. So nothing to it.

Now let’s go back over to R3 and this time we’re going to create an MOTD (message of the day) banner.

And I can have more than one banner on the router with no problem at all, so I’m not going to take off the previous one. I want you to see where they show up… and with the message of the day banner, this is a good way to say: “ the router is going to be down or the network is going to be unavailable tonight for example from 10 p.m. to 6:00 a.m. tomorrow)

I’ll do a quick write on the way out. And now when I telnet in what am I going to be shown?

Well you can see the order here. There is the message of the day and the log in banner is actually appearing right under that. So I’ll go ahead and log in and then log out and that’s all there is to it.

One more banner I want to show you and that is the exec banner

This is information that you want to show someone after they have successfully connected. So let’s just go ahead and do a banner exec

And you can see the two messages we got. We got message of the day first then we got the log in message.

I I log in and now I’m seeing the entire message.

Note:  you better stick with “$” or any character which is not used in your message.