Proxmox: GNS3 Lab 1

This is the first post in a computer networking mini-series following the University of the Pacific COMP 177 labs, using GNS3 hosted on my Proxmox server. In this post, we set up a very rudimentary network to test GNS3's functionality.
Proxmox: GNS3 Lab 1
In: Proxmox, GNS3, Computer Networking, Home Lab, UOP Network Project

This module is a part of a larger series of networking labs using GNS3 in Proxmox. Click here to be taken back to the first pages in the series.

Proxmox: GNS3 Remote Server
In this post, I demonstrate how to get GNS3 Remote Server running in Proxmox, and how to connect to it using a GNS3 client on Windows.





Reference Material

Lab 1 - GNS3 Setup | Pacific Cybersecurity

I'll be following along with this series of labs published by University of the Pacific for their COMP 177 class. The labs were originally published in 2020, but still offer some very valuable educational material.

I've already setup GNS3 in Proxmox on the previous blog post, so I will be picking up this lab on Step 5: Install Mikrotik Router into GNS3.





Installing Mikrotik Router

In my browser, I am going to http://gns3-vm-ip-or-fqdn in my browser and using GNS3 from the web interface. The COMP 177 lab documentation tells you to install the router from the Mikrotik download page, but we can use the pre-made templates in GNS3.

Click 'New Template'
'Install new appliance from the GNS server', click 'Next'
Filter on 'mikro...', click the 'Install' button
Click 'Download' next to the 6.x image of your choice
Unzip the file
Click 'Import' and choose the 'chr-6.49.6.img' file
You should see confirmation that the image was imported
Click 'Create'
Click 'Add template'

We now have a virtual MikroTik 6.49.6 router that we can use in our GNS3 project topologies.





Our First Network

Add the Hosts

Click this button
Click 'Add project'
Drag two GNS3 VPCs two the work area
Drag a MikroTik router on to the work area



Click the 'Add a link' button and copy the design in the lab instruction
I had to add some distance between nodes to reveal labels
Press the 'Start' button



Configure the MikroTik Interfaces

Right-click and choose 'Web console'

You should now have a console with direct access to the MikroTik command line. You should login with the username admin and an empty password. If prompted, you can decline to view the license. You will also be prompted to change the administrator password.

We are configuring the interfaces on the MikroTik. You'll the interface names we're configuring match the interface names in the GNS3 work area, ether1 and ether2.

  • ether1 is the gateway for the 10.11.12.0/24 network and is configured with the IP address of 10.11.12.254 and subnet mask of 255.255.255.0.
  • ether2 is the gateway for the 20.30.40.0/24 network and is configured with the IP address of 20.30.40.254 and subnet mask of 255.255.255.0.
Configuring the interfaces as per the lab



Configure the VPCs

Configure PC 1

Right-click VPC1 and choose 'Web console'

We are going to configure PC 1 with an IP address of 10.11.12.1 and a subnet mask of 255.255.255.0, putting it on the same subnet mask as the MikroTik's ether1 interface. We've also set the default gateway as 10.11.12.254.

Configure it as per the lab documentation



Configure PC 2

We are going to configure PC 2 with an IP address of 20.30.40.1 and a subnet mask of 255.255.255.0, putting it on the same subnet mask as the MikroTik's ether2 interface. We've also set the default gateway as 20.30.40.254.

Configure PC 2 as per the lab documentation



Test the Route

Per the lab instructions, we'll log into PC 1 and send an ICMP request to 20.30.40.1. This IP address is on a foreign subnet, so the packet will be sent to MikroTik's ether1 interface.

MikroTik will then check its routing table to see where to send the packet. 20.30.40.1 is a route that the MikroTik owns, so it moves the packet out on ether2 and onto PC 2.

PC 2 successfully receives the ICMP request and sends an ICMP reply. MikroTik again will be the responsible party for ensuring these two hosts can continue to communicate.

Proof that PC 1 can route through MikroTik to PC 2
You can stop all nodes and delete the project if you wish





Up Next: GNS3 Lab 2

Proxmox: GNS3 Lab 2
This is the second post in a computer networking mini-series following the University of the Pacific COMP 177 labs, using GNS3 hosted on my Proxmox server.
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