Minecraft

Introduction

We are to have some Minecraft servers on the Home Lab'. The general setup will be to have a Velocity server in front several Minecraft host Virtual Machines. Velocity works in a similar way to a Nginx reverse proxy whereby Pfsense forwards all Minecraft traffic to the Velocity server including the SNI and Velocity redirects traffic to the required hostname based on the DNS name. Cloudflare does not reverse proxy Minecraft traffic on the free tier and as we do not want to have to deal with random bots from the east so we will not leave the port open on the edge or Pfsense to random bots with port scanners. So we will use grey cloud at Cloudflare but DNS will point to a service like TCPShield and our firewalls only accept Minecraft traffic from their IP addresses and Velocity will only accept named servers and drop any unknown DNS names.

Installation

The installation will be in some distinct stages to enable each step to be proved to be working before proceeding to the next stage. First we setup a simple vanilla Minecraft server and set the firewall to port forward to it directly. Once that is proven to be working we will setup a Velocity server that will receive all 25565 traffic and forward it to the working Minecraft host. The next phase after the first host is getting traffic forwarded is to setup a second host and make sure velocity can forward to each, included in this step will be hardening the Velocity server with whatever security measures that it has available. When we are sure that Velocity is working properly we can work on the remote access stage, where we use TCPShield to proxy the service and have Cloudflare DNS only names setup with cherry.seaoffate.net and apple.seaoffate.net etc. From this point forward any new Minecraft servers will simply follow the same setup procedure.

The First Minecraft Host Configuration

The first Minecraft host needs to have enough resources to run the JVM and the server but as it just a vanilla server the specification does not need to be excessive. The table shows the highlights.

Item	Value	Notes
CPU	2
RAM	4GB
Swap	16gb	Additional disk allocated from Lexar SSD
Storage	96GB	Initially set at 32gb
Base OS	Debian 13.3	Server version
Hostname	Cherry
IP Address	192.168.100.30

Hardware Configuration

The Cherry host was created as a clone of the Debian template and then the basic specifications were improved so we will need to configure these extra items in the OS. First we need to identify the harddrive to use as the swap file

lsblk

The result is likely to show that the disk is likely to be /dev/sdb so we can set the swap space and enable it with

sudo mkswap /dev/sdb
sudo swapon /dev/sdb

To make the swap file persistent we edit the fstab

sudo nano /etc/fstab

Add the line:

/dev/sdb none swap sw 0 0

and remove or comment out the line that refers to

/dev/sda3

Before the storage sda main partition can be expanded to the full 96GB we have to remove the swap that is in the way so disable the existing swap with

sudo swapoff /dev/sda3

Open the disk utility to modify sda

sudo fdisk /dev/sda

Delete the swap partition with the option d, then type 3 to delete partition 3, then w to save and exit. The next thing to do is expand the Primary Root Partition so open fdisk again:

sudo fdisk /dev/sda

Delete the root partition:

• Type d (Delete)
• Type 2 (this only deletes the table entry, not the data).
• Type n (Create a new partition)
• Type p (Primary Partition)
• Type 2 (For Partition number 2)
• Type enter (Use default values for start sector)
• Type enter (Use default values for end sectors to fill the 96GB)
• CRITICAL: When asked if you want to remove the signature, type N.
• Type w (Save and exit)

To finalize Storage reboot to refresh the kernel partition table:

sudo systemctl reboot

When the VM reboots expand the filesystem into the new space:

sudo resize2fs /dev/sda2

We can verify the new swap and new sda size with

df -h

Now that the hardware is setup and configured we can proceed to the software installation

Software Installation

The software installation consists of updates, install the JVM and then install the Minecraft server. So to start as we do on most hosts with updates

sudo apt update
sudo apt upgrade

Install Necessary Utilities:

sudo apt install htop screen wget curl -y

Install Java 25:

sudo apt install openjdk-25-jre-headless -y

Verify Java Installation (Ensure it reports OpenJDK 25)

java -version 

Now we install the Minecraft server

Create the Server Directory:

mkdir ~/minecraft_server && cd ~/minecraft_server

Download the Server Software:

wget -O server.jar [1](https://piston-data.mojang.com/v1/objects/97ccd4c0ed3f81bbb7bfacddd1090b0c56f9bc51/server.jar)

Assuming the file downloaded we need an initial run to generate the file:

java -Xms1G -Xmx1G -jar server.jar nogui

When the file is first created it will not run until we Accept the EULA with the command:

sed -i 's/eula=false/eula=true/' eula.txt

We can create the Start Script:

nano start.sh

Paste in the following #!/bin/bash while true do echo "--- Starting Minecraft Server ---" java -Xms3G -Xmx3G \ --enable-native-access=ALL-UNNAMED \ -XX:+UseG1GC \ -XX:MaxGCPauseMillis=200 \ -XX:+UnlockExperimentalVMOptions \ -XX:+DisableExplicitGC \ -XX:+AlwaysPreTouch \ -jar server.jar nogui echo "--- Server stopped. Restarting in 5 seconds (Ctrl+C to cancel) ---" sleep 5 done Set the script to execute with

chmod +x start.sh

We can start the server with

./start.sh

Note we can type the command stop in the terminal and the server will save the world and stop it for 5 seconds during the 5 seconds, if we type ctrl+c it will end the script or if we just leave it the server will restart.

Enable External Access

We will need to access the server from outside world so we should forward the Minecraft port 25565 to the IP address of cherry. To make the port forward rules in Pfsense easier to understand we add an alias for cherry's IP address and a port alias for 25565. We add a port forward rule to Pfsense that says source IP 192.168.0.0/16 and any port, destination this firewall (self) Destination port Minecraft_standard, redirect IP_cherry port Minecraft_standard.

Testing

With this configuration loading a Minecraft client and setting the destination server to the WAN port IP address it will connect to the cherry host.

As part of the wider LAN setup we added a Adguard LXC to manage DNS. Part of the Adguard configuration was made to avoid the hairpin network access so a DNS redirect was made to forward *.seaoffate.net to Pfsense WAN and as the default domain name was set to seaoffate.net. So now when we have a destination of cherry Adguard will translate the hostname to cherry.seaoffate.net and redirect it to Pfsense, Pfsense will then forward to the relevant server. If that does not work as expected the next test would be to set the destination to cherry.seaoffate.net which should be redirected by Adguard.