Port-EX — Full-Range TCP Port Scanner

A fast TCP port scanner written in Python that scans all 65,535 ports on a target host and identifies open services. Built as a learning tool to understand how tools like Nmap perform service discovery at the socket level.

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What It Does

• Scans all 65,535 TCP ports on a given IP address
• Identifies open ports and resolves service names (HTTP, SSH, FTP, etc.)
• Displays a clean terminal banner via pyfiglet
• Configurable timeout to balance speed vs. accuracy

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Demo

 ____            _     _____  __
|  _ \ ___  _ __| |_  | ____|/ _|
| |_) / _ \| '__| __|  |  _|  |_
|  __/ (_) | |  | |_   | |___|  _|
|_|   \___/|_|   \__|  |_____|_|

Scanning 192.168.1.1 for open ports...

[+] Port 22 is open (ssh)
[+] Port 80 is open (http)
[+] Port 443 is open (https)
[+] Port 3306 is open (mysql)

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Installation

git clone https://github.com/parth0xu/Port-Scanner
cd Port-Scanner
pip install pyfiglet

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Usage

python3 port.py
# Enter target IP when prompted: 192.168.1.1

Legal notice: Only scan hosts you own or have explicit permission to test. Unauthorized port scanning may be illegal.

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How It Works

The scanner uses Python's socket library to attempt a TCP connection (connect_ex) on each port. A return value of 0 means the port accepted the connection — it's open. The socket.getservbyport() call maps port numbers to known service names from the system's /etc/services database.

result = s.connect_ex((target, port))
if result == 0:
    service = socket.getservbyport(port)
    print(f"[+] Port {port} is open ({service})")

Why connect_ex instead of connect? connect() raises an exception on failure. connect_ex() returns an error code — cleaner for looping over thousands of ports without try/except overhead on every closed port.

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Limitations & Planned Improvements

• Currently single-threaded — scanning all 65,535 ports is slow (~30+ min). Next version will use concurrent.futures.ThreadPoolExecutor for parallel scanning.
• Only TCP connect scan — no SYN (half-open) scan, which requires raw sockets and root privileges
• No banner grabbing yet — future version will attempt to read service banners for version detection

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Skills Demonstrated

Python Socket Programming Network Scanning TCP/IP Service Enumeration