Python: How to check if a port is open

import socket

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
result = sock.connect_ex(("127.0.0.1", 80))
if result == 0:
    print "Port is open"
else:
    print "Port is not open"

Original: stackoverflow

import socket
import time
 
HOST=""
PORT=""
TIMEOUT=1.0
 
while True:
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.settimeout(TIMEOUT)
        s.connect((HOST, PORT))
        print "[%s] Connection established" % time.strftime("%H:%M:%S")
        time.sleep(1)
        s.close()
    except:
        print "[%s] Cannot connect" % time.strftime("%H:%M:%S")

Original: sysadminpy.com