邮件系统——不能连接SMTP服务器

近期运行python脚本，

>>> import smtplib
>>> server = smtplib.SMTP('smtp.qq.com', 25)
第二行运行很长时间无结果后报错

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/smtplib.py", line 256, in __init__
    (code, msg) = self.connect(host, port)
  File "/usr/lib/python2.7/smtplib.py", line 316, in connect
    self.sock = self._get_socket(host, port, self.timeout)
  File "/usr/lib/python2.7/smtplib.py", line 291, in _get_socket
    return socket.create_connection((host, port), timeout)
  File "/usr/lib/python2.7/socket.py", line 571, in create_connection
    raise err
socket.error: [Errno 110] Connection timed out
ECS是ubuntu_14_04版本，忘各位大佬支持