Programming

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Packages / Socket

Check port

A port is a number associated with a specific service. 
 
"""Using Python to check if remote port is open and accessible
connect_ex() return an error indicator ...
instead of raising an exception
"""
import socket

def is_open(host, port):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.settimeout(1)
    res = s.connect_ex((host, port))
    if res == 0:
        print("%s %s open" % (host, port))
    else:
        print("%s %s closed" % (host, port))

is_open('python.org', 80)
is_open('python.org', 8080)

host = input('Host: ') # localhost
port = input('Port: ') # 80
is_open(host, int(port))

Open ports

We can see which ports are open for our system. 
 
"""Create instance of socket for every port
"""
import socket, threading

def scan_port(port):
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        try:
            res = s.connect(("127.0.0.1", port))
            print('Port %s is open' % port)
        except ConnectionRefusedError:
            pass

for i in range(10, 100):
    thread = threading.Thread(target=scan_port, args=[i])
    thread.start()

# Port 21 is open
# Port 25 is open
# Port 80 is open




References