域名到IP 报错socket.gaierror: [Errno 8] nodename nor servname provided, or not known

Python中如何通过域名，查看对应的IP？

请看如下代码：

import socket

hostname="www.baidu.com"
ip = socket.gethostbyname(hostname)

print "ip:", ip

看下执行结果：

ip: 112.80.248.75

如果配置的hostname有问题，或者说域名配置错误，就会出现如下报错：

Traceback (most recent call last):
  File "t.py", line 5, in 
    ip = socket.gethostbyname(hostname)
socket.gaierror: [Errno 8] nodename nor servname provided, or not known