Production Hardening Checklist
- •Zero Password Authentication: Enforce Ed25519 cryptographic SSH key authentication and disable root login.
- •Strict Default-Drop Firewall: Block all non-essential ingress ports with UFW / Iptables.
- •Fail2Ban Auto-Jailing: Automatically ban IP subnets exhibiting brute-force behavior.
The Essential Linux Server Hardening Baseline
Deploying a public Linux server without rigorous security hardening is an invitation to automated credential-stuffing bots, cryptominers, and ransomware operators. Within minutes of provisioning a public IP, scanners begin hammering SSH port 22. Here is the exact production security baseline enforced on Clouds Panel servers.
1. Hardening the OpenSSH Daemon
Edit /etc/ssh/sshd_config to disable password authentication, disallow direct root logins, and restrict authentication attempts:
/etc/ssh/sshd_config.d/security.conf
SSHD Config
# Enforce SSH Hardening Baseline
Port 2222
PermitRootLogin no
PasswordAuthentication no
ChallengeResponseAuthentication no
MaxAuthTries 3
LoginGraceTime 30
ClientAliveInterval 300
ClientAliveCountMax 2
AllowGroups sysadmin-deployers2. Configuring UFW Firewall with Default Drop
Lock down the network stack with an explicit allowlist policy:
firewall-setup.sh
Bash
# Reset UFW rules to strict baseline
sudo ufw default deny incoming
sudo ufw default allow outgoing
# Allow custom SSH and Web ports
sudo ufw allow 2222/tcp comment 'Hardened SSH'
sudo ufw allow 80/tcp comment 'HTTP'
sudo ufw allow 443/tcp comment 'HTTPS'
# Enable firewall
sudo ufw enable
sudo ufw status verbose3. Automated Security Patches with Unattended-Upgrades
Kernel vulnerabilities must be patched immediately. Enable automated Debian/Ubuntu unattended upgrades so critical CVEs are resolved automatically without waiting for manual operational cycles.