我想知道为什么我听说过几次直接inputIP作为MXlogging是不好的。 大多数ISPbuild议我们使用邮件服务器IP创buildAlogging，并将该logging用作MXlogging。
我之前input了一个名为MX的IP，并且大部分时间都在工作，但是有些情况是无效的。 似乎无法find原因。
有没有合理的解释呢？
与DNS和邮件交换相关的各种RFC指定MXlogging由一个首选值和一个带有地址（ A ）logging的域名组成。
请参阅RFC 2181，第10.3节：
10.3. MX and NS records The domain name used as the value of a NS resource record, or part of the value of a MX resource record must not be an alias. Not only is the specification clear on this point, but using an alias in either of these positions neither works as well as might be hoped, nor well fulfills the ambition that may have led to this approach. This domain name must have as its value one or more address records. Currently those will be A records, however in the future other record types giving addressing information may be acceptable. It can also have other RRs, but never a CNAME RR.
共振通常由接收MTA给出。 通常，基于IP的mxlogging被阻止，因为垃圾邮件发送者一直使用它们