128-55-143-63.static.reverse.lstn.net has no MX records.
Question and response
Question
dig 128-55-143-63.static.reverse.lstn.net. MX
Answer
The response has no answer records.
Authority
lstn.net. 2560 SOA ns1.limestonenetworks.com. noc.limestonenetworks.com. 1772808207 16384 2048 1048576 2560
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0