156.in-addr.mrf.va.web.rcn.net has no MX records.
Question and response
Question
dig 156.in-addr.mrf.va.web.rcn.net. MX
Answer
The response has no answer records.
Authority
mrf.va.web.rcn.net. 3600 SOA master.dns.rcn.net. hostmaster.rcn.com. 2016021201 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0