Port Scanning & Security Checks – The Ninja’s Secret Weapon!

Now we enter the shadowy world of network security. Today, you learn the ninja art of port scanning – the ability to see what doors are open on a machine and who left their security wide open!

But beware… with great power comes great responsibility (and maybe some angry sysadmins if you misuse it 😬).

What Are Ports? – The Secret Entryways

Think of a computer like a fortress 🏰, Ports are the doors through which data flows.

• Port 22 → SSH (Remote login 🖥️)
• Port 80 → HTTP (Web browsing 🌍)
• Port 443 → HTTPS (Secure web browsing 🔒)
• Port 3306 → MySQL (Databases 📊)

Your mission, should you choose to accept it, is to find open ports and check if the system is exposed to threats.

The Art of Stealth Scanning – Using nmap

A true ninja never barges in through the front door – they scan quietly! nmap is the ultimate tool for scanning open ports, detecting services, and even identifying operating systems.

Command	What It Does
nmap scanme.nmap.org	🔍 Basic scan of a target
nmap -sS scanme.nmap.org	🕶 Stealth scan (avoids detection)
nmap -p 22,80,443 scanme.nmap.org	🎯 Scan specific ports
nmap -A scanme.nmap.org	🕵️ Detect OS and services

💡 Example:

nmap -p 22,80,443 scanme.nmap.org  # Check if SSH, HTTP, or HTTPS is open

If port 22 is open, the system allows remote logins (potential vulnerability!). 😨

Who’s Listening? – Using netcat

netcat (nc) is a ninja tool for checking open ports and even chatting secretly through a network.

Command	What It Does
nc -zv scanme.nmap.org 22	🕵️ Check if SSH is open
nc -zv scanme.nmap.org 80	🌍 Check if a web server is running
nc -lvnp 4444	🔊 Listen on port 4444 (for backdoors 😏)

💡 Example:

nc -zv scanme.nmap.org 443  # Check if HTTPS is open

If a port is open, it means a service is running there – and possibly exploitable. 😈

Firewall Checks – Is My Defense Strong?

A fortress is useless without strong walls. Test your own firewall to see what ports are open and if attackers can slip in.

Command	What It Does
sudo ufw status	🔥 Check if firewall is active
sudo iptables -L	🛡 View current firewall rules
nmap -Pn YOUR_IP	🎯 Check your own attack surface

💡 Example:

sudo ufw status  # Make sure your firewall is blocking unwanted access

If firewall is off, your system is wide open to attackers! 😱