DNS查询结果的一点

Question

菜鸟一枚，请问一下，在利用host命令查询DNS记录的时候，红色圈出来的那个数字表示什么意思。。。

例如：10 relay.XXX.cn中的10是什么意思。。。

Answer 1

MX record priority

Mail is delivered to the mail exchange server with the lowest preference number (highest priority), so the MX record you use for mail routing should have the lowest preference number, typically 0. For example, use 0 for your mail routing record, and 10 for the record for validating that you own your domain.