to limit the filesystem from getting bigger:
sudo journalctl --vacuum-time=7d
sudo journalctl --vacuum-size=200M
adding SWAP space:
sudo fallocate -l 2G /swapfile
sudo chmod 600 /swapfile
ls -lh /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
sudo cp /etc/fstab /etc/fstab.bak
echo "/swapfile none swap sw 0 0" | sudo tee -a /etc/fstab
update & remove unnecessary packages:
apt-get update
apt-get upgrade
sudo apt install sudo ufw htop fail2ban
sudo systemctl disable multipathd
sudo systemctl disable udisks2
sudo apt-get remove --purge udisks2 packagekit snapd fwupd polkitd upower
sudo apt autoremove
add user with SUDO permissions:
adduser myuser
usermod -aG sudo myuser
the machine FW:
ufw reset
ufw limit 22/tcp
ufw limit 8122/tcp
ufw allow 8168/tcp
ufw enable
Fail2ban:
sudo mkdir /var/run/fail2ban
sudo cp /etc/fail2ban/fail2ban.conf /etc/fail2ban/fail2ban.local
sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local
sudo systemctl restart fail2ban
sudo fail2ban-client status
for ubuntu 24 – if install of fail2ban fails (ubuntu 24.04) – the fix is here: https://discuss.frappe.io/t/fail2ban-fails-on-ubuntu-24-04-lts/127658