Registro IPv4
host: esmtp.biz
class: IN
ttl: 300
type: A
ip: 204.16.169.54

Servidores DNS Principal (mname) y Secundario (rname)
host: esmtp.biz
class: IN
ttl: 86400
type: SOA
mname: ns1.changeip.org
rname: noc.changeip.com
serial: 3
refresh: 3600
retry: 150
expire: 604800
minimum-ttl: 31

Información TXT
host: esmtp.biz
class: IN
ttl: 3600
type: TXT
txt: v=spf1 ip4:204.16.168.0/21 -all
entries: Array