simple_port_scanner.py

import sys
import socket
from datetime import datetime

if(len(sys.argv) < 2):
    print("Usage: python3 %s <host>"%sys.argv[0])
    sys.exit(1)

ip = socket.gethostbyname(sys.argv[1])

try:
    print("Started the port scanning at ",datetime.now())
    for port in range(20,81):
        sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        sock.settimeout(1)
        open = sock.connect_ex((ip,port))
        print("Cheking for port %d"%port)
        if open == 0:
            print("The port %d is open"%port) 
    print("Port scanning end at ",datetime.now())
except KeyboardInterrupt:
    print("I'm interrupted, mayday, mayday..")
    sys.exit(1)
except socket.gaierror:
    print("Cannot resolve hostname!")
    sys.exit(1)