Registro IPv4
host: school-textbook.com
class: IN
ttl: 300
type: A
ip: 80.85.141.91

Servidores DNS Principal (mname) y Secundario (rname)
host: school-textbook.com
class: IN
ttl: 1800
type: SOA
mname: adaline.ns.cloudflare.com
rname: dns.cloudflare.com
serial: 2417195593
refresh: 10000
retry: 2400
expire: 604800
minimum-ttl: 1800