Python: how to check if a port of a remote host is open

In this article we will see how to check if a port of a remote host is open or not with Python.

This check requires the creation of a socket towards the remote host on the specified port indicating a timeout in seconds which allows us to avoid useless waiting in the request.

import socket

def check_port(host='127.0.0.1', port=80, timeout=2):
    sck = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sck.settimeout(timeout)
    try:
        sck.connect((host, int(port)))
        sck.shutdown(socket.SHUT_RDWR)
        return True
    except:
        return False
    finally:
        sck.close()

If the port is open, the boolean value True is returned. In case of exceptions, such as a connection timeout or other network-level errors, the value False is returned. To optimize resource management, the finally block closes the socket in both cases.