python判断设备是否联网的方法

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import socket

def isNetOK(testserver):
  s=socket.socket()
  s.settimeout(3)
  try:
    status = s.connect_ex(testserver)
    if status == 0:
      s.close()
      return True
    else:
      return False
  except Exception as e:
    return False

def isNetChainOK(testserver=('www.baidu.com',443)):
  isOK = isNetOK(testserver)
  return isOK


def isNetUSAOK(testserver=('www.google.com',443)):
  isOK = isNetOK(testserver)
  return isOK

def isNetYouTubeOK(testserver=('www.youtube.com',443)):
  isOK = isNetOK(testserver)
  return isOK

def main():

  chinanet = isNetChainOK()
  print chinanet
  usanet = isNetUSAOK()
  print usanet
  youtubenet = isNetYouTubeOK()
  print youtubenet


if __name__ == '__main__':
  main()