求助

我在dos界面下运行nslookup查询出新浪的mx记录如下：
Non-authoritative answer:
sina.com.cn MX preference = 10, mail exchanger = sinamx.sina.com.cn

sina.com.cn nameserver = ns1.sina.com.cn
sina.com.cn nameserver = ns2.sina.com.cn
sina.com.cn nameserver = ns3.sina.com.cn
sinamx.sina.com.cn internet address = 202.108.3.187
sinamx.sina.com.cn internet address = 202.108.3.188
sinamx.sina.com.cn internet address = 202.108.3.186
ns1.sina.com.cn internet address = 202.106.184.166
ns3.sina.com.cn internet address = 202.108.44.55
请问这些都是代表什么意思，谢谢