windows中是自带的，不用安装，直接在cmd窗口直接使用
Linux中需要安装：
yum -y install bind-utils
nslookup www.baidu.com
[root@bogon ~]# nslookup www.baidu.com
Server: 192.168.13.2
Address: 192.168.13.2#53
Non-authoritative answer:
www.baidu.com canonical name = www.a.shifen.com.
Name: www.a.shifen.com
Address: 14.215.177.38
Name: www.a.shifen.com
Address: 14.215.177.39