System settings

Update system

sudo apt update
sudo apt upgrade
do-release-upgrade

reboot

hostname

vim /etc/hostname

user

adduser ubuntu
usermod -aG sudo ubuntu

ssh config

ssh-copy-id -p 50000 ubuntu@12.98.23.12

# vim /etc/ssh/sshd_config
PermitRootLogin no
PasswordAuthentication no
PubkeyAuthentication yes

service ssh restart
ssh -p 50000 root@12.98.23.12