co.ir has no MX records.
Question and response
Question
dig co.ir. MX
Answer
The response has no answer records.
Authority
co.ir. 873 SOA a.nic.ir. info.nic.ir. 2602241430 1800 900 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0