lantun

lantun is a networking tool that makes it possible to expose local ports over a secure tunnel to the internet. lantun is not a reverse proxy, so both the host and client need to run the lantun client.

Tunnel system

A host can expose a port over the internet by creating a HostTunnel, which is identified by a 64 character long ID. Everyone who knows this ID can create a ClientTunnel to connect to the host.

A HostTunnel can be bound to a specific IP address and port like 127.0.0.1:8080/tcp. The ClientTunnel can expose the tunneled connection on a IP address and port on the client network like 127.0.0.1:5000/tcp.

This would establish a tunneled connection between client and host.

Host: 127.0.0.1:8080/tcp <-> Client: 127.0.0.1:5000/tcp

So the client can now essentially access the hosts service on port 8080 over their own local port 5000.

Usage

Lets say the Host wants to expose a minecraft server running on port 25565.

On the host side run:

$ lantun add-host 127.0.0.1:25565 tcp mc-server 

Tunnel "mc-server" with local addr 127.0.0.1:25565/tcp created.
The public secret is "e929b2f2cc170c71ec7b3e71cc78b041c29545095ee0c1d74baba545c5091b02"

To add a client tunnel on the client side, use:
  lantun add-client e929b2f2cc170c71ec7b3e71cc78b041c29545095ee0c1d74baba545c5091b02 127.0.0.1:25565 tcp <name>

On the client side run:

$ lantun add-client e929b2f2cc170c71ec7b3e71cc78b041c29545095ee0c1d74baba545c5091b02 127.0.0.1:25565 tcp <name>

Now start the lantun program on both sides and keep it running to tunnel the connection:

$ lantun

The client can now join the host's server by connecting to 127.0.0.1:25565.

[!NOTE] If configured properly other devices on the client network can also join the host's server by connecting to the local IP address of the client (which is running lantun).

see lantun --help for more options.

Details

Under the hood lantun uses iroh to establish peer-to-peer connections. If a direct connection is not possible a relay server will be used. Tunnel traffic is encrypted using the private and public keys of the tunnel.

Location of the lantun config file:

• Linux: ~/.config/lantun/config.toml
• Windows: %APPDATA%/lantun/config.toml
• MacOS: ~/Library/Application Support/lantun/config.toml