network-scanner

Your Python script is a straightforward network scanner that:

• Accepts an IP address or domain name,
• Resolves domain names to IP addresses,
• Pings the host to check if it’s alive,
• Scans a list of common ports to see which ones are open,
• Prints the results.

On Windows (CMD or PowerShell)

git clone https://github.com/naveenyadav369/network-scanner.git && cd network-scanner && python scanner.py

Quick Review & Suggestions:

1. Ping Handling:

   • Works well cross-platform using ping -n (Windows) or -c (Linux/macOS).
   • You correctly check for "unreachable" in ping output and handle exceptions.

2. Port Scanning:

   • Uses socket.connect_ex with a timeout for quick port scanning.
   • Closes the socket after each attempt to avoid resource leaks.

3. Domain Resolution:

   • Uses socket.gethostbyname() to resolve domains.

4. User Interaction:

   • Good prompting for whether to continue if ping fails.

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Potential Improvements:

1. Better Host IP Validation:

Right now, this code treats any input consisting only of digits and dots as an IP:

if all(c.isdigit() or c == '.' for c in target):
    ip = target

This can misclassify invalid IPs. Consider using ipaddress module for robust IP validation:

import ipaddress

def is_valid_ip(ip):
    try:
        ipaddress.ip_address(ip)
        return True
    except ValueError:
        return False

Then replace your check with:

if is_valid_ip(target):
    ip = target
else:
    # resolve domain

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2. Port Scan Parallelization:

Currently, ports are scanned sequentially which can be slow. Using threading or multiprocessing can speed up scans:

import threading

def scan_port(host, port, open_ports):
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.settimeout(0.5)
    try:
        if sock.connect_ex((host, port)) == 0:
            open_ports.append(port)
    except socket.error:
        pass
    finally:
        sock.close()

def scan_ports_parallel(host, ports):
    open_ports = []
    threads = []
    for port in ports:
        t = threading.Thread(target=scan_port, args=(host, port, open_ports))
        t.start()
        threads.append(t)
    for t in threads:
        t.join()
    return open_ports

---

3. Improved Output:

Add port service names (like FTP, SSH) to results to improve readability:

PORTS_INFO = {
    21: 'FTP',
    22: 'SSH',
    23: 'Telnet',
    25: 'SMTP',
    53: 'DNS',
    80: 'HTTP',
    110: 'POP3',
    139: 'NetBIOS',
    143: 'IMAP',
    443: 'HTTPS',
    445: 'Microsoft DS',
    3389: 'Remote Desktop'
}

# Later in your print loop:
for port in open_ports:
    print(f"  Port {port} ({PORTS_INFO.get(port, 'Unknown')}) is open")

---

4. Run as Administrator Warning:

Note that ping and port scanning may require administrative privileges on some systems to function properly.

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Final Note

Your script is solid for learning and small scans. For more advanced scanning, consider libraries like scapy or nmap bindings (python-nmap).

If you want, I can help you refactor your script with these improvements! Would you like that?