Registro DMARC
v=DMARC1;p=reject;sp=reject;adkim=s;aspf=s

Servidores DNS Principal (mname) y Secundario (rname)
host: miamicardiac.com
class: IN
ttl: 1800
type: SOA
mname: blue.foundationdns.com
rname: dns.cloudflare.com
serial: 2389174292
refresh: 10000
retry: 2400
expire: 604800
minimum-ttl: 1800

Información TXT
host: miamicardiac.com
class: IN
ttl: 300
type: TXT
txt: v=spf1 -all
entries: Array