KmDDNS

Automatically keeps your KmDDNS record up to date so players can always find your server — even when your IP changes.

No router config. No static IP. Just install and run.

What it does

KmDDNS gives your Minecraft server a permanent address like myserver.ddns.kmathers.co.uk. Whenever your server starts, the mod checks your current public IP and updates the DNS record automatically. Players always connect to the same address.

Tunnel mode takes this further — if you can't or don't want to forward ports, the mod connects to a relay that routes player traffic through KmDDNS infrastructure. No port forwarding required at all.

Features

Keeps your subdomain pointing at your current IP automatically
Sends your server's MOTD and player count to the KmDDNS API (shown on the lookup page)
Tunnel mode — no port forwarding needed, traffic is proxied through a relay
In-game setup wizard — register or configure everything without leaving the game
/kmddns status to see your current address, IP, and connection state at a glance
Configurable heartbeat interval, port, and tags

Setup

1. Get a subdomain

Run /kmddns setup in-game to open the wizard. You can:

Register a new subdomain — pick a name and get a token on the spot
Use an existing token — if you already have a KmDDNS account

The wizard walks you through port detection, update interval, and whether to use tunnel mode. When you confirm, it saves the config and starts immediately.

2. That's it

Your server will now appear at yourname.ddns.kmathers.co.uk. Players connect using that address.

Tunnel mode

If you're behind CGNAT, a strict firewall, or just don't want to mess with port forwarding, enable tunnel mode during setup.

In tunnel mode:

The mod keeps a WebSocket connection open to KmDDNS
When a player connects to your subdomain, the relay routes them through to your server
Your server doesn't need to be reachable from the internet directly

Enable it during /kmddns setup, or set tunnel = true in the config and toggle it on via the API.

Commands

Command	Description
`/kmddns status`	Show current IP, subdomain, tunnel state, and last update time
`/kmddns setup`	Open the interactive setup wizard
`/kmddns setup token <token>`	Configure with an existing token
`/kmddns setup new`	Register a new subdomain

Config

The config file is created automatically at config/kmddns.toml on first launch.

[kmddns]
enabled = true
token = "your-token-here"
api_base = "https://ddns.kmathers.co.uk/v1"
port = 0                  # 0 = auto-detect from server.properties
update_interval = 300     # seconds between heartbeats (minimum 30)
tags = ["minecraft"]
metadata_motd = true      # send server MOTD to the API
metadata_player_count = true
log_updates = true
tunnel = false            # set true to use tunnel mode

Requirements

Server-side only — players do not need this mod
Fabric or NeoForge
Minecraft 1.21.1, 1.21.4, 1.21.5, or 1.21.11
A KmDDNS account (free, created via /kmddns setup new)

A quick note

I build these tools for fun and for the community. Keeping everything running does have real maintenance costs, and even $1 goes a long way.

If you enjoy the tools and want to give back, you can support me here: Buy me a coffee. No pressure either way — thanks for being here.