_netblocks.ioflood.net has no MX records.
Question and response
Question
dig _netblocks.ioflood.net. MX
Answer
The response has no answer records.
Authority
ioflood.net. 180 SOA ns1.ioflood.com. support.ioflood.com. 2026022001 43200 3600 1209600 180
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0