Introduction Lab

Introduction to Netkit - ABR Lab

For this lab we are going to create three machines a, b, and r, launch them using lstart, and finally analyse the contents of their .startup files. The resulting folder structure should look roughly as follows:

$ ls

a/ a.startup b/ b.startup lab.conf lab.dep r/ r.startup

The final network mapping is illustrated below.

note

Please ensure Netkit is installed correctly prior to following these steps. This lab will not work without Netkit running on your machine.

Creating a, b, and r

Start by creating a folder for our lab, which we will name abr. You may want to do this within an nklabs directory, which can then be used for future labs. Change directory (cd) to this new abr folder.

$ mkdir -p nklabs/abr

$ cd nklabs/abr

Create .startup files for each machine, a lab.conf file, and a lab.dep file. The braces {...} are used here to allow you to create multiple files at once (brace expansion). In other words, {a, b}.txt would result in a.txt and b.txt.

$ touch {a,b,r}.startup lab.{conf,dep}

Next, edit the contents of each file using your favourite text editor (e.g. gedit, vim, nano, etc.)

$ gedit {a,b,r}.startup lab.{conf,dep} &

We are going to put in the parameters from the network diagram into the various files. Understanding the contents of the files is left as an exercise for the reader. It is worth noting that you don't have to set a MAC address - Netkit will do this for you, however you can override this as shown below.

note

It is advisable to type out the contents of the files below manually rather than copy-pasting them.

a.startup

ifconfig eth0 hw ether 00:aa:aa:aa:aa:aa:aa

ifconfig eth0 172.28.97.42/29

route add default gw 172.28.97.41

b.startup

ifconfig eth0 hw ether 00:bb:bb:bb:bb:bb:bb

ifconfig eth0 10.0.0.2/27

route add default gw 10.0.0.1

r.startup

ifconfig eth1 hw ether 00:81:81:81:81:81:81

ifconfig eth1 172.28.97.41/29

ifconfig eth2 hw ether 00:82:82:82:82:82:82

ifconfig eth2 10.0.0.1/27

lab.conf

a[0]=lanX

r[1]=lanX

r[2]=lanY

b[0]=lanY

Before launching Netkit we need to create a folder for each machine.

$ mkdir a b r

Finally, we are ready to launch the machines. Run lstart and you should see terminal windows pop up for machines a, b, and r.

$ lstart

To kill the machines, just run lcrash in your original terminal window.

$ lcrash

Voilà! You have successfully created your first Netkit lab.

🐸