port_forwarding

Port forwarding

To configure their devices, students first access a proxy container. There is one proxy container for every AS, and from a proxy container students can only access the devices that are within their AS.

The access to the proxy container (from the real Internet) is made possible by installing SSH tunnels that forward SSH connections to the corresponding proxy container based on the port number used. We now explain how to setup the port forwarding.

First of all, make sure the following options are set to true in /etc/sshd_config on your host server:

GatewayPorts yes
PasswordAuthentication yes
AllowTcpForwarding yes

Then restart the ssh service:

sudo service ssh restart

Finally, you must use the script portforwarding.sh that configures all the SSH tunnels automatically based on the configuration files. It also opens the corresponding ports using ufw. You can run this script with the following command from the platform directory:

sudo ./utils/ssh/portforwarding.sh

In case you want to delete the SSH forwarding rules that were created, you can use the following command:

for pid in $(ps aux | grep ssh | grep StrictHostKeyChecking | tr -s ' ' | cut -f 2 -d ' '); do sudo kill -9 $pid; done

⚠️ This command might also delete SSH tunnels that are unrelated to the mini-Internet.