modbender Host Hardening
Secure a Linux server running OpenClaw in under 2 minutes.
SSH — Key-Only Auth
sed -i 's/^#*PermitRootLogin.*/PermitRootLogin prohibit-password/' /etc/ssh/sshd_config
sed -i 's/^#*PasswordAuthentication.*/PasswordAuthentication no/' /etc/ssh/sshd_config
systemctl restart ssh
Firewall — Deny All Except SSH
ufw default deny incoming
ufw default allow outgoing
ufw allow ssh
yes | ufw enable
Add more rules as needed (e.g. ufw allow 443 for HTTPS).
Fail2ban — Brute-Force Protection
apt-get install -y fail2ban
systemctl enable --now fail2ban
Default config protects SSH. For custom jails: /etc/fail2ban/jail.local.
OpenClaw Credentials
chmod 700 ~/.openclaw/credentials
OpenClaw Gateway Service
Auto-restart on reboot:
cat > /etc/systemd/system/openclaw-gateway.service << 'EOF'
[Unit]
Description=OpenClaw Gateway
After=network-online.target
Wants=network-online.target
[Service]
Type=simple
ExecStart=/usr/bin/env openclaw gateway
Restart=always
RestartSec=5
User=root
WorkingDirectory=/root/.openclaw
Environment=HOME=/root
[Install]
WantedBy=multi-user.target
EOF
systemctl daemon-reload && systemctl enable openclaw-gateway
Verify
ufw status # active, SSH allowed
systemctl is-active fail2ban # active
grep PasswordAuthentication /etc/ssh/sshd_config # no
stat -c %a ~/.openclaw/credentials # 700
systemctl is-enabled openclaw-gateway # enabled
Lessons
- On Ubuntu, SSH service is
sshnotsshd - AWS security groups provide network-level filtering but UFW is defense-in-depth
- Always verify you have key-based SSH access before disabling password auth