Registro DMARC
v=DMARC1; p=reject;

Servidores DNS Principal (mname) y Secundario (rname)
host: btgroup.mx
class: IN
ttl: 1800
type: SOA
mname: hank.ns.cloudflare.com
rname: dns.cloudflare.com
serial: 2360909075
refresh: 10000
retry: 2400
expire: 604800
minimum-ttl: 1800

Información TXT
host: btgroup.mx
class: IN
ttl: 300
type: TXT
txt: v=spf1 ip4:213.32.147.163 include:mars.spacemail.io a mx -all
entries: Array