231.20.178.in-addr.arpa has no MX records.
Question and response
Question
dig 231.20.178.in-addr.arpa. MX
Answer
The response has no answer records.
Authority
231.20.178.in-addr.arpa. 3600 SOA rdns1.spd.net.tr. spd.net.tr. 2026022601 900 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0