How to open a tunnel to another device or server

Since app version 1.3.0

A tunnel can lead not only to this computer but also to a device on your network or a server on the internet: enter its address in the "Destination address" field. Not every plan allows a server on the internet:

Plan	Basic	Pro	Ultra
Where a tunnel leads	this computer and devices at home	servers on the internet too	servers on the internet too

How to set the address

App

1. Under "Tunnels", click "Create tunnel" (if you already have tunnels, it's the plus button above the list).
2. In "Destination address", enter the address with its port, for example 192.168.1.20:25565. Below the field the app shows where the tunnel will lead: "This computer", "A device on your network: it will be reachable from the internet", "Domain" or "A server on the internet".
3. Click "Create tunnel": the tunnel card shows its address for your friends.

If your plan doesn't allow internet addresses, for an IP address on the internet the field says "Internet addresses are available on a higher plan", and a domain that leads to the internet fails to open with "On your plan a tunnel can only lead to this computer or a device on your home network.": pick a device on your network or change the plan.

To change the destination of an existing tunnel, open its "Settings" tab, enter the new address in the "General settings" block and click "Save changes". The tunnel's address for your friends stays the same. A game server's tunnel leads to this computer only.

Command line

--host sets another computer:

proximamp tcp 25565 --host 192.168.1.20

If your plan doesn't allow computers on the internet, the program says "your plan does not allow sending visitors to a computer on the internet", and with a device key made without --usage, "this device key may not see the plan…": what to do. If the host leads to a tunnel, the program says "that host leads back into ProximaMP: give the computer where your server runs".

A device of your network named by --host becomes visible from the internet without a warning: let only your own people in.

To change a ready tunnel's host, stop the command (Ctrl+C) and run it with the new host and the old address, or the address for your friends changes:

proximamp tcp 25565 --host <new host> --address <old address>

What the tunnel card shows

• "A local network device is reachable from the internet": anyone with the tunnel's address can reach this device. Let in only the people you trust: access by IP.
• "Destination not found": the name in "Destination address" leads nowhere right now, and visitors don't get through. Check the name; use only a name you control.
• "The destination leads to a proximamp node": the field holds a tunnel's address, not your service's. Enter the address of the computer your service runs on. When you create the tunnel, the app says the same: "The destination leads back to a proximamp node…".

What to keep in mind

• Docker on Windows. A container with a published port (docker run -p 8080:80 …) is reached as this computer: enter localhost:8080. The container's IP, such as 172.17.0.2, and its name don't work from Windows.
• Tailscale. Addresses like 100.x.y.z count as internet addresses: they need a plan that allows a server on the internet.
• UDP. A tunnel to another address accepts replies only from that address and port: a service that answers from another port doesn't work through it.
• A website by its name. A website given by its domain usually doesn't open through a tunnel: in Host it gets the tunnel's address instead of its own name (HTTPS link). A router or NAS page over http:// works.

Check

From a phone on mobile data, open the tunnel's address or connect to it from the game: you should get what runs on that device.