MyTurn - SSH Port Forwarding Server

Setup

You can use the provided docker-compose.yml and the prebuilt Docker image at code.leon.wtf/leon/myturn. You need to make the following adjustments:

• Copy config.example.json to data/config.json and adjust the values (see "config.json" below)
• Adjust the port mappings in docker-compose.yml accordingly
• Make sure the specified ports are accessible, e.g. configure your networks firewall to allow incomping packets on the specified port range and the SSH port

config.json

Key	Description
service_addr	Where the application INSIDE the Docker container should listen on.
external_service_hostname	Hostname where MyTurn is accessible externally.
external_service_port	Port where MyTurn is accessible externally.
port_range_start	Start of the port range, users can bind their services to.
port_range_end	End of the port range, users can bind their services to.
registration_secret	A secret, users must enter when they want to register. If not set, the registration does not require a secret.
host_key_path	The private host key MyTurn should use for itself.

How to use it?

MyTurn uses your SSH public key and a chosen username to identify you. You need to register youself, via the register user:

• ssh -p <port> [-i <path-to-ssh-key>] register@<hostname>, e.g. ssh -p 222 register@myturn.example.org
  • If you don't specify the -i flag the SSH agent selects one of your keys for you
• Enter the registration secret (if configured)
• Enter your wanted username

You can then use your username to request a port forwarding:

• ssh -p <port> [-i <path-to-ssh-key>] -R 0.0.0.0:<public-port>:127.0.0.1:<local-port> <username>@<myturn.example.org, e.g. ssh -p 222 -R 0.0.0.0:6101:127.0.0.1:8080 leon@myturn.example.org

MyTurn verifies your SSH key and, if authenticated, opens a virutal terminal to control (e.g. stop) the port forwarding. The connection needs to stay open as long as you want to use the SSH port forwarding.

SSH commands

You can manage your SSH keys via SSH commands. This allows you to add multiple keys to your account. Execute a command with: ssh -p <port> [-i <path-to-ssh-key>] <username>@<hostname> <command>.

These commands are available:

• help: Shows a help page
• get-keys: Gets a list of all your public keys with their IDs
• add-key <key>: Adds a new key to your account
• remove-key <key-id>: Removes a key by it's key ID displayed in get-keys

Commands in MyTurn port forwarding terminal

• help: Shows a help page
• status: Unimplemented
• stop: Closes the connection and deallocates the port