Registro DMARC
v=DMARC1; p=reject; pct=100; rua=mailto:a@dmarc.facebookmail.com; ruf=mailto:fb-dmarc@datafeeds.phishlabs.com;

Servidores DNS Principal (mname) y Secundario (rname)
host: tfbnw.net
class: IN
ttl: 2146
type: SOA
mname: a.ns.facebook.com
rname: dns.facebook.com
serial: 4207849484
refresh: 14400
retry: 1800
expire: 604800
minimum-ttl: 3600

Servidor de Correo
host: tfbnw.net
class: IN
ttl: 5746
type: MX
pri: 10
target: smtpin.vvv.facebook.com

Información TXT
host: tfbnw.net
class: IN
ttl: 5746
type: TXT
txt: v=spf1 include:_spf.fb.com include:_spf.facebook.com -all
entries: Array