Registro DMARC
v=DMARC1; p=reject; fo=1; rua=mailto:dmarc_rua@emaildefense.proofpoint.com; ruf=mailto:dmarc_ruf@emaildefense.proofpoint.com

Servidores DNS Principal (mname) y Secundario (rname)
host: marathonpetroleum.us
class: IN
ttl: 3600
type: SOA
mname: ns1-06.azure-dns.com
rname: azuredns-hostmaster.microsoft.com
serial: 1
refresh: 3600
retry: 300
expire: 2419200
minimum-ttl: 300

Información TXT
host: marathonpetroleum.us
class: IN
ttl: 600
type: TXT
txt: v=spf1 -all
entries: Array