Server Security

SSH hardening, firewalls, fail2ban, DDoS/CC defense, incident response and backups

• Hardening SSH: Change the Port, Disable Root, Enforce Key-Only Login

  Lock down SSH in three moves: switch to a non-standard port, block direct root login, and allow key-based auth only.

• Firewall Basics: ufw, firewalld, and iptables

  Open the ports your server needs, block the rest, and never lock yourself out — with ufw on Ubuntu, firewalld on RHEL, or raw iptables underneath.

• Block Brute-Force Attacks and Bad IPs with fail2ban

  Watch your logs, catch failed logins, and automatically ban attacking IPs to add a self-defending layer to your server.

• DDoS and CC Attacks: How They Work and How to Defend

  Learn the difference between network-layer DDoS and application-layer CC, make the most of single-host rate limiting, and understand where that defense ends and CDN plus scrubbing must take over.

• What to Do When Your Server Is Compromised: Investigate, Clean Up, and Respond

  A complete incident-response walkthrough — from spotting the signs to isolating, preserving evidence, and hardening. The golden rule: back up important data for forensics first, and when in doubt, rebuild.

• Backup & Snapshot Strategy: Losing No Data at the Lowest Cost

  With the 3-2-1 rule, a few lines of script, and a single `cron` job, your server's data can survive disk failures, fat-finger deletes, and ransomware.

• Auditing Open Ports and Shutting Down Risky Services

  Use ss and nmap to find out what your server is actually exposing, pull the wrong things back inside, and hold a minimal attack surface.

• Managing Passwords, SSH Keys, and API Keys Securely

  Lock down every entry point to your servers and accounts with strong passwords, SSH keys, and tightly scoped API keys.

• Keeping Your System Updated: Patch Vulnerabilities Promptly

  Patching is the cheapest, highest-return security control you have. Learn to update by hand, enable automatic security updates, handle kernel reboots, and back up before you start.

• Hiding Your Origin IP Behind a CDN: Stop Direct Attacks, Scanning, and Web Threats

  Tuck your real IP behind a CDN, accept only origin-pull traffic, and let a WAF, rate limiting, and CAPTCHAs absorb attacks before they reach your server.