socket：判断网络是否连接

import socket

def isNetChainOK(testserver=('www.baidu.com', 443)):
    so = socket.socket()
    so.settimeout(3)
    try:
        status = so.connect_ex(testserver)
        if status == 0:
            so.close()
            print("网络正常！")
        else:
            print("网络异常，请检查网络！")
    except Exception:
        print("网络异常，请检查网络！")

if __name__ == '__main__':
    isNetChainOK()