This section details how to setup the entirety of our topology. The controller file can be taken from the Ryu Controller subdirectory. The steps below can be modified to build a custom topology for any other particular use case.
The script files provided can be used to speed up the setup of the topology. It is recommended to automate the setup of your custom topology using scripts.
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Create the Kali, Ubuntu and Metasploitable VMs.
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The Kali and Metasploitable VMs' network adapters are connected to 2 separate Host-Only networks.
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For the Ubuntu VM, one network adapter is connected to the Kali Host-Only network, and the other to the Metasploitable one.
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VMs requiring access to the internet are attached with a NAT adapter.
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Install the required packages within Ubuntu:
sudo apt install python-ryu mininet xterm -
Run the Ryu controller Python file through ryu-manager:
ryu-manager <file.py> -
Any packages/tools that are to be used within Mininet can be installed in the Ubuntu VM itself - Mininet hosts have access to all commands and the filesystem of the underlying OS.
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Start the Mininet topology and use XTerm to access a particular host’s shell:
sudo python <file.py>
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Ensure the Mininet switch is up:
sudo ifconfig <switch-name> -
Add the NAT port (which is providing internet access to Ubuntu) to the switch:
sudo ovs-vsctl add-port <switch-name> enp0sx -
Assign an IP to the switch through DHCP:
sudo dhclient <switch-name> -
Within a Mininet host (connected to the above switch) which is to be connected to the internet:
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Clear adapter’s config:
sudo ifconfig <host-name>-eth0 0 -
Assign an IP through DHCP:
sudo dhclient <host-name>-eth0 -
Add a DNS for accessing common URLs:
echo "nameserver 8.8.8.8" | sudo tee /etc/resolv.conf
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Create the OVS bridges using
sudo ovs-vsctl add-br <bridge name> -
Connect these bridges to the adapters:
sudo ovs-vsctl add-port <bridge name> <enp0sx> -
Give IP Addresses to these bridges within the same IP range of the respective VM's host-only network:
sudo ip addr add <ip range> dev <bridge name> -
IP Forwarding is required as well:
sudo sysctl -w net.ipv4.ip_forward=1 -
Add the Linux routing:
sudo ip route add <ip range> via <ip> -
Enable the bridges:
sudo ip link set dev <bridge name> up
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For Metasploitable - receive an IP through DHCP:
sudo dhclient eth0 -
Add default routes within the Kali and Metasploitable VMs (to their respective bridges):
route add default gw <bridge ip>