239.75.119.in-addr.arpa has no MX records.
Question and response
Question
dig 239.75.119.in-addr.arpa. MX
Answer
The response has no answer records.
Authority
239.75.119.in-addr.arpa. 86400 SOA ns2.bit-isle.co.jp. root.bit-isle.co.jp. 2008071600 3600 1800 86400 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0