md1.csmaildealer.com has no MX records.
Question and response
Question
dig md1.csmaildealer.com. MX
Answer
The response has no answer records.
Authority
csmaildealer.com. 3600 SOA asns1.customer.ne.jp. n-wata.nttpc.co.jp. 1436157700 3600 1800 3628800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0