Servidores DNS Principal (mname) y Secundario (rname)
host: shoecritic.com
class: IN
ttl: 1341
type: SOA
mname: ns-cloud-e1.googledomains.com
rname: dns-admin.google.com
serial: 3
refresh: 21600
retry: 3600
expire: 1209600
minimum-ttl: 300