Question and response
Question
dig mx.iplanisp.com. NS
Answer
mx.iplanisp.com. 5 CNAME mx.iplannetworks.net.
Authority
iplannetworks.net. 3581 SOA dns1.iplanisp.com.ar. hostmaster.iplan.com.ar. 2018122806 3600 600 1400000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0