Make Queries For _x.dns.com

Open a command line terminal window.

run the following two commands:
nslookup -q=cname _x.dnsByComodo.net ns1.dnsByComodo.net
nslookup -q=cname _x.dnsByComodo.net ns2.dnsByComodo.net

Example answer
_x.dnsByComodo.net canonical name = t8eddnadns3.dnsByComodo.net.