Servidores DNS Principal (mname) y Secundario (rname)
host: nstld.org
class: IN
ttl: 21600
type: SOA
mname: a1.verisigndns.com
rname: dns.constellix.com
serial: 2019030811
refresh: 43200
retry: 3600
expire: 1209600
minimum-ttl: 180

Servidor de Correo
host: nstld.org
class: IN
ttl: 14400
type: MX
pri: 10
target: custmx.cscdns.net