Create The Server

Follow the instructions here.

Keep in mind the IP address you want to use

Forge/NeoForge

When creating a modded server, look for the server download.
On curseforge, you need to download the server from the app
Another note about using modpacks, if you are using mscs, then you have to configure the server using the same method as they show.

The run script in the server directory needs to look like the listing below. Also make sure the script has execute permissions: sudo chmod +x run.sh.

#!/usr/bin/env sh
# Forge requires a configured set of both JVM and program arguments.
# Add custom JVM arguments to the user_jvm_args.txt
# Add custom program arguments {such as nogui} to this file in the next line before the "$@" or
#  pass them to this script directly
java @user_jvm_args.txt @libraries/net/neoforged/neoforge/21.1.77/unix_args.txt "$@"

To get the paths setup correctly, run the following script:

Forge

sudo sed -i "\|@[^\"]|s|@|@$(pwd)/|" run.sh;
sudo sed -i "s|\"\$@|--nogui &|g" run.sh;
sudo sed -i "s|libraries|$(pwd)/libraries|g" run.sh;
sudo sed -i "s|libraries|$(pwd)/libraries|g" libraries/net/minecraftforge/forge/*/unix_args.txt

Neoforge

sudo sed -i "\|@[^\"]|s|@|@$(pwd)/|" run.sh;
sudo sed -i "s|\"\$@|--nogui &|g" run.sh;
sudo sed -i "s|libraries|$(pwd)/libraries|g" run.sh;
sudo sed -i "s|libraries|$(pwd)/libraries|g" libraries/net/neoforged/neoforge/*/unix_args.txt

You'll then need to modify the mscs server properties file and include the following lines:

mscs-client-version=#.##.#
mscs-server-version=#.##.#
mscs-server-command=/opt/mscs/server/[server-directory]/run.sh
mscs-server-url=

DDNS

Create a DDNS account at Dynu.
Use IP Chicken to ensure the DNS service points to the correct IP address.

Port Forwarding

Port forward the external IP address to the internal one on chuggy.