Assuming a fresh install of Ubuntu 22.04LTS, accepting default options and no extra packages except OpenSSH server to login.
Install zip/unzip:
apt-get update; apt-get install zip unzip
Download archive for Tekkit2 (as of 20221202):
wget https://servers.technicpack.net/Technic/servers/tekkit-2/Tekkit-2_Server_v1.1.3.zip
Unzip:
unzip Tekkit-2_Server_v1.1.3.zip
Install Java and add Repos:
add-apt-repository ppa:webupd8team/java apt install openjdk-8-jdk
Attempt to launch to confirm server is working:
chmod +x LaunchServer.sh ./LaunchServer.sh
Should take several minutes to load, depending on hardware. If this works, set up cron to similar to below to launch server upon reboot:
root@syr-tekkit:# cat /etc/cron.d/root_gameserver @reboot root sleep 5 && cd /home/asullivan && /usr/bin/screen -dmS gameserver-screen /home/asullivan/LaunchServer.sh
Open up port 25565 to internet while server is running to connect. Use the Technic Launcher.