refuse-port-scanner

Proposed solution

Certainly! Below is a simple Python TCP port scanner that scans a specified host for open ports within a given range. This script uses the `socket` library to attempt connections on each port and reports which ones are open. Remember to use this responsibly and only scan hosts you own or have explicit permission to test.

```python
import socket
import concurrent.futures

def scan_port(ip, port):
    try:
        # Create a new socket
        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
            # Set a timeout for the socket
            s.settimeout(1)
            # Try to connect to the port
            result = s.connect_ex((ip, port))
            # If the result is 0, the port is open
            if result == 0:
                return port
    except Exception as e:
        pass
    return None

def main():
    host = input("Enter the host IP address: ")
    start_port = int(input("Enter the start port number: "))
    end_port = int(input("Enter the end port number: "))

    print(f"Scanning ports on {host} from {start_port} to {end_port}...\n")

    # Use ThreadPoolExecutor to scan multiple ports concurrently
    with concurrent.futures.ThreadPoolExecutor(max_workers=100) as executor:
        # Create a list of futures
        futures = [executor.submit(scan_port, host, port) for port in range(start_port, end_port + 1)]
        
        # Iterate through the futures as they complete
        for future in concurrent.futures.as_completed(futures):
            result = future.result()
            if result:
                print(f"Port {result} is open.")

if __name__ == "__main__":
    main()
```

This script prompts the user for the host IP address, the start port, and the end port, then scans the specified range of ports concurrently for open ports. It uses a thread pool to speed up the scanning process by attempting multiple connections in parallel. Note that the `max_workers` parameter in `ThreadPoolExecutor` can be adjusted based on your system's capabilities and the number of ports you wish to scan. A higher number of workers can speed up the scan but may also increase system load.

Please ensure you have permission to scan the target host, as unauthorized scanning can be considered illegal or malicious activity in many contexts.