Objectives

In this lab, you will test out the VTP management interfaces available to instructors.

Remember to ask the instructors if you have any questions about what you’re seeing or how you might use it!

GNS3 web UI

Login

Go to your own web interface at <yourname>.local.nsrc.org

Follow the link to Admin > gns3 and login. See the documentation for how to retrieve the username and password from your host.

Note

It was generated randomly when you first ran sslsetup in the vtp-proxy container. Everyone in your group will be using the same password, across all the containers.

Restore from snapshot

IN the GNS3 web UI, restore your entire lab to the snapshot l3-3-nat following the process described in the presentation.

Go back to the student web interface, and get a console on one of the edge switches.

Login to the switch. Notice how it now requires a username and password: the credentials required are documented in the CNDO topology documentation.

Go into “enable” mode. Again, it needs an enable password, which is given in the documentation.

This is the state you’d expect the lab to be in after the students have done all the exercises up to and including the NAT lab.

You should be able to ping the Internet (e.g. ping 8.8.8.8); this proves the routing through the core L3 switch is working, and the NAT on the border router is working.

gns3man UI

Break a login

Get someone else in your group to login to one of the devices in your network (say the bdr1 router) and break its login:

conf t
username campus1 secret aksdjfnkajsndkfjn
end
wr mem
logout

Now, you go back to the console, and check you can no longer login to this device with the correct username and password!

Login to gns3man

Go back to your own web interface at <yourname>.local.nsrc.org

This time, follow Admin > gns3man and login.

To fix the problem:

• Click the “Edit” link next to the device in question (this will stop it, if it’s already running)

• It should show you the NVRAM config in a text box

• Scroll down to find the username line:

  username campus1 secret 9 $9$mylA5XIrIcbPjk$5lC0lfTonh159mZRnhR0cLVT1HCIcX0/r4VTeyo/6WY

• Change this to

  username campus1 secret <the-correct-password>

• Click the Import button at the bottom

• If the device had been automatically stopped, it will be automatically restarted. If you had manually stopped it, you’ll have to click Start.

Now go back to the console, refresh the page, and login again. You should be able to login with the correct password.

Note

An alternate way to fix this would be to restore the device from a snapshot; that’s a more drastic change which would lose any other changes the student had done.

Conclusion

You’ve now seen the essential parts of the VTP container management.

And at worst, you can always destroy and rebuild the entire container - a great way to ensure a fresh start at the beginning of a new course.

To do that you would do:

incus rebuild ttt:cndo1 <yourname>

(You don’t need to do this now, unless you want to).