Constant LAN port?

Question

Occasionally, a friend wants to join me, playing on my Minecraft world, which I run locally on my computer.

We don't want to use VPN or other stuff, so we currently do it using this procedure:

I start Minecraft, load my world, then click "open to LAN". I note the random generated port.
I open my NAT router configuration and forward that port to my computer
I open that port in the Windows Firewall.
I look at myip.is to find out my current public IP, which changes every 24h.
I give my buddy my public IP address, and the port, so he can connect to "[ip-address]:[port]"
After the game session, I will remove the port from the NAT Port forwarding table and in the Windows Firewall (because it will be invalid in the next session)t

I do know that step 4 can be dropped if I use a Dynamic-DNS service. I think I will set one up.

But I find it very annoying to always re-configure my Windows Firewall and the NAT Port Forwarding Table, just because Minecraft always listens to a random port.

What can I do to make the procedure more easy? Can't I simply tell Minecraft to always use the same port when playing "local" in LAN (actually WAN, because I use port-forwarding).

vpzomtrrfrt · Answer

No, LAN worlds always use random ports. You would need to run a dedicated server to choose your port. You can move the world folder to the server and either rename it to "world" or change server.properties to use its name.

Answered by vpzomtrrfrt on January 23, 2021

PCMC · Answer

Press the windows key + R on Windows 10, windows key + X on Windows 8, or select Start > Run on other windows PCs.

Then type %appdata%.minecraft
open the folder called something like, "worlds" and select the world name you want in the server. Then press ctrl+C to copy it.

Go to your server folder, and delete the old world. Paste the new world in, and rename it "world".

Areeb · Answer

There's a forge mod to configure lan servers and I'm pretty sure it works with vanilla clients, so your friend won't need it.

It allows you to configure which port the server runs on, so that should solve your problem.

Link: Custom Lan Mod

Niels Basjes · Answer

The Open to Lan on a Minecraft client always be used a random port, you cannot change that.
UPDATE: You cannot change the port in the GUI.
Turns out there is a commandline (only) option that allows you to set fix the port number. https://minecraft.gamepedia.com/Commands/publish .
This allows you to fix the port number for your "Open to Lan" game. Because in most of these scenarios the IP address will still be randomly selected the experimental tool below may still prove useful.

However this open-to-lan server then starts announcing on the network where this Minecraft server can be found.
I recently created a PoC that listens for those announcements and sets up a proxy that makes this server available on a fixed port.
This PoC is quick and dirty (requires Linux) and intends just to show this is a possibility.
In case you want to see it I put it on github
https://github.com/nielsbasjes/minecraft-open-to-lan

LeoColman · Answer

According to Minecraft's Wiki, you can use the /publish command.
/publish [port]

port: integer

Must be a 32-bit integer number. And it must be between 0 and 65535 (inclusive).
    The port to host on. If not specified, a random port above 1024 is chosen.

Constant LAN port?

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