Skip to content

E02 First Switches

Back to the Course Schedule

Back to the Material: Ethernet, VLANs and Switching

Video: Instructions for E02

Danger: Watch these videos if necessary for more info

This laboratory is step by step instructed, but later when asked to apply the skills given here (at E04)... lot of confusion has happened.

Thus these videos are here to help!

Video: virtual machine adapters, ping & how to draw

Video: Configuring VLAN tagged/untagged

Example Video: E02 step-by-step, Exercise done in teaching by the teacher during spring 2022

I explain long and in detail, thus long video but, you can't go wrong with this one. Hopefully. Same video description has time tags for E01 - E05.



Importing a Network Switch -virtual machine(s)

Import the switch.ova file to VirtualBox similarly as instructed in the first assignment.

Bug: There is a compatibility problem with switch.ova and AMD Ryzen processors

Remember in MAC Address Policy to Generate new MAC addresses for all network adapters

Warning: This is when your responsibility as a Network Administrator begins

This is your data network environment/laboratory. If you mess things up in your exercises, you have to clean it. Your mother won't be here to do it.

Check the settings

Example: Take the adapters of switch1 and locate them into the correct networks in VirtualBox


Host-only adapter has to be created in Linux/Apple products

Image of the problem


Solution to the problem

Tools -> Network -> Create





Clone the switch!

Lets create the second switch Network_switch 2 by cloning the first one.


Rename the switch accordingly (e.g. Network_switch 2).


Do a full clone of the switch.

Example: Set the adapters on Network_switch 2 as instructed below.





When adapters are set correctly, the topology would look like this.


Accessing and using the Network Switch

Tip: Configuring the Switch -video

Start the virtual machine. Let the Network Switch boot up. Once finished you should be at a black screen containing text as follows:


Warning: It takes a little bit of time for the (pending-AAA) login: to stop... be patient

You might have to (left-mouse) click into the console screen and press enter once for the login: _ to appear

Once only login: _ is visible, you can login using the credentials given in the README.txt:

login: admin

Which should bring you to the terminal.


You can look at the configuration by typing in show configuration.


You can hit spacebar to continue or q to stop.

Example: You might want to name the console output of the devices

To not get confused between the switch consoles...

Naming in EXOS (Switches)

EXOS-VM.1# configure snmp sysName [name]

Enabling Ports

The switch starts with ports disabled. We need to start enabling them.

The term port means physical ports of the switch!

Some might get this confused with TCP/UDP port numbers...

If you get confused, check this FAQ

Problem 13 - How do the (Network) Adapters in VirtualBox work?

This can be done by enabling one port at a time.

enable ports 1
enable ports 2

Or by defining a range.

enable ports 1-2
You can verify the state of the port with the command show ports info. The command can be a range e.g. show ports 1-2 info.

Enabled port - Flags: E !a

Disabled port - Flags: D !a

Configuring End Devices manually

Remember to clone the other Lubuntu also according to the topology!

Move the Lubuntus network adapters:

  • first lubuntu VM to LAN1 and
  • second lubuntu VM to LAN3!

Draw a picture of your topology (based on the network adapter settings in VirtualBox).

At this point on the course we do not know about IP addressing or subnets, but we can still manually assign addresses by following the steps below.

Start up the lubuntu virtual machine and right click the network icon in the bottom right. Left click Edit Connections...


Follow the numbers in the figure below by left clicking each one


Under Editing Wired connection 1 window, press + Add and write down the following addresses into the box.


Press Save and close the window.

Once done you can double click the QTerminal and verify that the operating system has taken the IP-address into use by writing the command ip addr

Warning: Notice! Save doesn't mean take into use

if the address doesn't come into use, you can press the network logo on the bottom right (in Lubuntu) to force the interface up/down


Do the same for Lubuntu2, but use an IP address of

Testing connectivity

Once the End Devices have been addressed, verify the connection by using ping tool. Depending on which virtual machine terminal you are on... ping the opposing machine's IP address. Lubuntu1 should ping and Lubuntu2 should ping

Successful ping should look like this
lubuntu@lubuntu-VirtualBox:~$ ping
PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=64 time=1.05 ms
64 bytes from icmp_seq=2 ttl=64 time=2.14 ms
64 bytes from icmp_seq=3 ttl=64 time=2.10 ms
64 bytes from icmp_seq=4 ttl=64 time=2.22 ms
--- ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3003ms
rtt min/avg/max/mdev = 1.051/1.878/2.221/0.482 ms

You can stop pinging by selecting the terminal and pressing CTRL+C.

Investigating Forwarding Tables

Leave the pings on so that there is active traffic in the network.

Lets look at the forwarding tables of the switches with the command show fdb.

show fdb command on switch1


show fdb command on switch2


Adding VLANs

Creating the VLAN

Lets create our first VLAN with the command create vlan workstations

The VLAN needs an Ethernet 802.1Q tag, which can be declared with the command configure vlan workstations tag 5

The switch now has the VLAN declared, but not in use.

Assigning untagged ports to a vlan

By default, all of the ports on the switch are currently in VLAN default and as untagged. Thus we need to remove it before adding workstations vlan to the ports.

You can do this with the command:

configure vlan default delete ports all.

The port towards the Lubuntu virtual machine should be untagged in VLAN workstations.

configure vlan workstations add ports 1 untagged

Creating tagged Ports

The port towards the other switch should be tagged

configure vlan workstations add ports 2 tagged

Do the same for the other switch, but be vary of the port assignments!

If necessary, look at your topology and Problem 13 - How do the (Network) Adapters in VirtualBox work?

Testing connectivity

If you left the ping on while doing changes in the network configuration, the ping should have stopped when you were doing the network configuration changes

64 bytes from icmp_seq=462 ttl=64 time=2.19 ms
64 bytes from icmp_seq=463 ttl=64 time=2.06 ms
From icmp_seq=495 Destination Host Unreachable
From icmp_seq=496 Destination Host Unreachable
And then continued once working configuration is in place

From icmp_seq=538 Destination Host Unreachable
From icmp_seq=539 Destination Host Unreachable
64 bytes from icmp_seq=540 ttl=64 time=2003 ms
64 bytes from icmp_seq=541 ttl=64 time=1003 ms
64 bytes from icmp_seq=542 ttl=64 time=3.59 ms
64 bytes from icmp_seq=543 ttl=64 time=2.33 ms

Danger: If ping doesn't work, try to solve the problem yourself

There is a small detail, which requires thought while following/copying the instructions.


Ask for assistance, if necessary.

Saving configuration

Switches forget their configuration unless it is saved!

You can save the configuration with save command. The switch will prompt you for confirmation.

EXOS-VM.1 # save
The configuration file primary.cfg already exists.
Do you want to save configuration to primary.cfg and overwrite it? (y/N) Yes

Saving configuration primary.cfg  on master .. done!
Configuration saved to primary.cfg successfully.
EXOS-VM.2 # 

This will ensure that the configuration is written onto the hard disk of the switch. The virtual machine switch will remember the configuration even after restarting/booting the virtual machine.

Wiresharking an Ethernet Frame

Create a third Lubuntu Wireshark virtual machine.

Change the adapter settings of the virtual machine.

  1. Settings -> Network -> Adapter 1
  2. goto advanced
  3. Change Promiscuous Mode to Allow All !!!
  4. Verify that Attach to is Internal Network
  5. Select the network name according to the cable/network you want to investigate (e.g. LAN2)

Now the Lubuntu Wireshark can investigate all network traffic seen on the selected cable/network.

Tip: Problem 15 - What does wireshark do 'visually' / 'as a drawing'?

Capturing Traffic

Boot up the Lubuntu Wireshark virtual machine. Start wireshark from the desktop. Start the recording on wireshark by selecting eth0.


Traffic should start to tricle down the interface row by row.


You can stop the recording by pressing the red square in the control ribbon of Wireshark.

Saving the Recording

Select File -> Save As... -> Locate a correct folder -> Name the file -> Press Save

Now the Network traffic capture is a file on the disk of the virtual machine. And can be investigated thoroughly.


Warning: Leaving the recording on starts to deplete the resources of the virtual machine!

Going through the fields

Choose one row. Check the following fields and record them into your exercise document as figures.

  1. Find the source MAC address
  2. What is the Ethertype
  3. Find the source IP address
  4. What is the Payload of the Ethernet frame in the selected capture row?

Recording configuration from the switches

Do this individually to both switches.

Address the first switch (switch1) with the command

conf vlan workstations ipaddress

This isn't best practice, but will suffice at the start of our studies

As there are no strong passwords set .... the network devices are vulnerable to brute force attacks.

Address the second switch (switch2) with the command

conf vlan workstations ipaddress

Enable SSH -server on both of the switches by with the command below

EXOS-VM.8 # enable ssh2 port 22
WARNING: Generating new server host key
This could take up to 1 minute and cannot be cancelled. Continue? (y/N) Yes

Key Generated.

Go to a Lubuntu Machine

Ensure you have the clipboard of your computer enabled correctly in VirtualBox


SSH from the Lubuntu Qterminal to the switch. The prompt first asks if you want to trust the newly created SSH keys. Answer yes. Then the prompt asks for an password. Note that the admin's password is the same as in the switch virtual machine console.

lubuntu@lubuntu-virtualbox:~$ ssh admin@ authenticity of host ' (' can't be established.
RSA key fingerprint is SHA256:D/HVddWrAq+EPG+ytADya/kM9e7lioVWasK2ENvCTCk.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '' (RSA) to the list of known hosts.
admin@'s password: 
Copyright (C) 1996-2020 Extreme Networks. All rights reserved.
This product is protected by one or more US patents listed at along with their foreign counterparts.

Press the <tab> or '?' key at any time for completions.
Remember to save your configuration changes.

* EXOS-VM.1 # show configuration

This will print out the configuration of your switch (if you press spacebar enough). Copy it into your documentation (from both devices).

This video is spoken in Finnish. ENABLE THE ENGLISH SUBTITLES

Example video of the saving process

What to document of the exercise?

Document in the repository & /documentation/E02/ -folder:

  • Screenshots, analysis & text while doing
  • Proof of working connectivity tests
  • show fdb -command
  • Wireshark inspections
  • Configuration of all the network devices
  • Your topology drawings (physical, logical, etc)

Back to the Schedule?

Back to the Course Schedule


This course and its materials are written by Karo Saharinen and licenced by Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license.

Creative Commons -licence